216 R.I. Code R. 216-RICR-50-05-1.6

Current through December 26, 2024

Section 216-RICR-50-05-1.6 - Filtration and Disinfection

1.6.1General Requirements

A. The requirements of this Section constitute Rhode Island's primary drinking water regulations. This Part establishes criteria under which filtration is required as a treatment technique for PWS supplied by a surface water source, or a groundwater source under the direct influence of surface water also referred to as § 1.6 PWS. This Part establishes treatment technique requirements in lieu of maximum contaminant levels for the following contaminants: Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, Cryptosporidium, and turbidity. Each § 1.6 PWS must provide treatment of that source water that complies with these treatment technique requirements.

B. The treatment technique requirements consist of installing and properly operating water treatment processes which reliably achieve:

1. At least 99.9 percent (3-log) removal and/or inactivation of Giardia lamblia cysts between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer, and

2. At least 99.99 percent (4-log) removal and or inactivation of viruses between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer.

3. At least 99 percent (2-log) removal of Cryptosporidium between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer for filtered PWS, or Cryptosporidium control under the watershed control plan for unfiltered PWS.

4. Compliance with the profiling and benchmark requirements under the provisions of § 1.6.3(G) of this Part.

C. A § 1.6 PWS is considered to be in compliance with the requirements of § 1.6.1(B) of this Part, if:

1. It meets the requirements for avoiding filtration in § 1.6.2 of this Part and the disinfection requirements in § 1.6.3 of this Part; OR

2. It meets the filtration requirements in § 1.6.4 of this Part and the disinfection requirements in § 1.6.3 of this Part.

D. Each § 1.6 PWS must be operated by qualified personnel who meet the requirements of the Rules and Regulations Pertaining to the Certification of Public Drinking Water Treatment and Transmission and Distribution Operators promulgated pursuant to the authority set forth in R.I. Gen. Laws Chapter 23-65.

E. § 1.6 PWS that served fewer than ten thousand (10,000) people beginning January 1, 2002 but currently serve or will serve at least ten thousand (10,000) people before January 1, 2005 must comply with all the requirements listed in this Filtration and Disinfection Document for PWSs serving at least ten thousand (10,000) people as soon as those PWS begin serving at least ten thousand (10,000) people. These PWS must also consult with the Director to establish a disinfection benchmark. If a significant change is made to the disinfection practice, these PWS must consult with the Director prior to making such change as stated in § 1.6.3(G)(4) including, but not limited to, §§ 1.6.3(G)(4)(a)((1)) through ((4)) of this Part.

F. Recycle Provisions: All § 1.6 PWS that employ conventional filtration or direct filtration treatment and that recycle spent filter backwash water, thickener supernatant, or liquids from dewatering processes must meet the requirements in §§ 1.6.1(F)(1) and 1.6.8(D) of this Part.

1. Treatment Technique Requirement. Any PWS that recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes must return these flows through the processes of a PWS's existing conventional or direct filtration system as defined in 40 C.F.R. § 141.2 or at an alternate location approved by the Director.

1.6.2Criteria for Avoiding Filtration

A. A PWS that uses a surface water source must meet all of the conditions of §§ 1.6.2(D) and (E) of this Part and is subject to § 1.6.2(F) of this Part unless the Director has determined in writing that filtration is required.

B. A PWS that uses a groundwater source under the direct influence of surface water must meet all of the conditions of §§ 1.6.2(D) and (E) of this Part and is subject to § 1.6.2(F) of this Part, eighteen (18) months after the Director determines that it is under the direct influence of surface water, unless the Director has determined in writing that filtration is required.

C. Within eighteen (18) months of the failure of a PWS using surface water or a groundwater source under the direct influence of surface water to meet any one (1) of the requirements of §§ 1.6.2(D) or (E) of this Part, the PWS must have installed filtration and meet the criteria for filtered systems specified in § 1.6.4 of this Part.

D. Source Water Quality Conditions:

1. The fecal coliform concentration must be equal to or less than 20/100ml or the total coliform concentration must be equal to or less than 100/100 ml (measured as specified in § 1.21 of this Part) in representative samples of the source water immediately prior to the first or only point of disinfectant application in at least ninety (90) percent of the samples taken for the six (6) previous months that the PWS served water to the public on an ongoing basis.

2. If a PWS measures both fecal and total coliforms, the fecal coliform criterion, but not the total coliform criterion, must be met.

3. The turbidity level cannot exceed 5 NTU (measured as specified in § 1.21 of this Part) in representative samples of the source water immediately prior to the first or only point of disinfectant application.

E. Site Specific Conditions:

1. Compliance

a. The PWS must meet the requirements of § 1.6.3(E)(1) of this Part, at least eleven (11) of the twelve (12) previous months that the PWS served water to the public on an ongoing basis.

b. The PWS must meet the requirements of § 1.6.3(E)(2) and (3) of this Part, at all times the PWS serves water to the public.

c. The PWS must meet the requirements of § 1.6.3(E)(4) of this Part, on an ongoing basis.

2. The PWS must maintain a watershed control program which minimizes the potential for contamination by Giardia lamblia cysts, Cryptosporidium oocysts and viruses in the source water. During the onsite inspection (discussed in § 1.6.2(F)(3) of this Part), the adequacy of a watershed control program will be determined by the Director. The adequacy of a program to limit potential contamination by Giardia lamblia cysts, Cryptosporidium oocysts, and viruses must include, but not be limited to, the following measures:

a. The comprehensiveness of the watershed review;

b. The effectiveness of the PWS's program to monitor and control detrimental activities occurring in the watershed; and

c. The extent to which the PWS has maximized land ownership and/or controlled land use within the watershed. At a minimum, the watershed control program must:

(1) Characterize the watershed hydrology and land ownership;

(2) Identify watershed characteristics and activities which may have an adverse effect on source water quality; and

(3) Monitor the occurrence of activities which may have an adverse effect on source water quality.

d. The PWS must demonstrate through ownership and/or written agreements with landowners within the watershed that it can control all human activities which may have an adverse impact on the microbiological quality of the source water.

e. The PWS must submit an annual report to the Director that identifies any special concerns about the watershed and how they are being handled; describes activities in the watershed that affect water quality; and projects what adverse activities are expected to occur in the future and describes how the PWS expects to address them. Approved watershed protection plans or wellhead protection plans may be used to the extent that they are applicable.

3. The PWS must be subject to an annual on-site inspection to assess the watershed control program and disinfection treatment process. A report of the on-site inspection summarizing all findings must be prepared every year. The on-site inspection must indicate to the Director's satisfaction that the watershed control program and disinfection treatment process are adequately designed and maintained. The on-site inspection will include but not be limited to:

a. A review of the effectiveness of the watershed control program;

b. A review of the physical condition of the source intake and how well it is protected;

c. A review of the PWS's equipment maintenance program to ensure there is low probability for failure of the disinfection process;

d. An inspection of the disinfection equipment for physical deterioration;

e. A review of operating procedures;

f. A review of data records to ensure that all required tests are being conducted and recorded and disinfection is effectively practiced; and

g. Identification of any improvements which are needed in the equipment, PWS maintenance and operation, or data collection.

4. The PWS must not have been identified as a source of a waterborne disease outbreak, or if it has been so identified, the PWS must have been modified sufficiently to prevent another such occurrence as determined by the Director.

5. The PWS must comply with the maximum contaminant level (MCL) for total coliforms in §§ 1.16.4 and 1.17.1 of this Part at least eleven (11) of the twelve (12) previous months that the PWS served water to the public on an ongoing basis, unless the Director determines that failure to meet this requirement was not caused by a deficiency in treatment of the source water.

6. All § 1.6 PWS of this Part must comply with the requirements for total trihalomethanes, haloacetic acids (five), bromate, chlorite, chlorine, chloramines, and chlorine dioxide in § 1.8 of this Part.

F. Treatment Technique Violations

1. A PWS that fails to meet any one (1) of the criteria in §§ 1.6.2(E) or (F) of this Part, or for which the Director has determined that filtration is required in writing and fails to install filtration by the date specified is in violation.

2. A PWS that has not installed filtration is in violation of a treatment technique requirement if:

a. The turbidity level in a representative sample of the source water immediately prior to the first or only point of disinfection application exceeds 5 NTU; or

b. The PWS is identified as a source of a waterborne disease outbreak.

1.6.3Disinfection

A. A PWS that uses a surface water source and does not provide filtration treatment must provide the disinfection treatment specified in § 1.6.3(E) of this Part unless the Director determines that filtration is required in writing.

B. A PWS that uses a groundwater source under the direct influence of surface water and does not provide filtration treatment must provide disinfection treatment specified in § 1.6.3(E) of this Part eighteen (18) months after the Director determines that the groundwater source is under the influence of surface water, unless the Director has determined that filtration is required in writing.

C. If the Director has determined that filtration is required, the PWS must comply with any interim disinfection requirements the Director deems necessary before filtration is installed. A PWS that uses a surface water source that provides filtration treatment must provide the disinfection treatment specified in § 1.6.3(F) of this Part beginning June 29, 1993 or beginning when filtration is installed, whichever is later.

D. A PWS that uses a groundwater source under the direct influence of surface water and provides filtration treatment must provide disinfection treatment as specified in § 1.6.3(F) of this Part, beginning when filtration is installed. Failure to meet any requirement of this Section is a treatment technique violation.

E. Disinfection Requirements for PWS That Do Not Provide Filtration

1. The disinfection treatment must be sufficient to ensure at least 99.9 percent (3-log) inactivation of Giardia lamblia cysts and 99.99 percent (4-log) inactivation of viruses, every day the PWS serves water to the public, except any one (1) day each month. Each day a PWS serves water to the public, the PWS must calculate the CT value(s) from the PWS's treatment parameters, using the procedure specified in §§ 1.6.6(A)(3) and (4) of this Part, and determine whether this value is sufficient to achieve the specified inactivation rates for Giardia lamblia cysts and viruses.

a. If a PWS uses a disinfectant other than chlorine, the PWS may demonstrate to the Director, through the use of a protocol approved by the Director for on-site disinfection challenge studies or other information satisfactory to the Director, that the CT99.9 values other than those specified in Tables 2.1 and 3.1 in § 1.6.8 of this Part, or other operational parameters are adequate to demonstrate that the PWS is achieving minimum inactivation rates required by § 1.6.3(E)(1) of this Part.

2. The disinfection system must have either:

a. Redundant components, including an auxiliary power supply with automatic start-up and alarm to ensure that disinfectant application is maintained continuously while water is being delivered to the distribution system; or

b. Automatic shut-off of delivery of water to the distribution system whenever there is less than 0.2 mg/L of residual disinfectant concentration in the water.

(1) If the Director determines that automatic shut-off would cause unreasonable risk to health or interfere with fire protection, the PWS must comply with § 1.6.3(E)(2)(a) of this Part.

3. The residual disinfectant concentration in the water entering the distribution system measured as specified in § 1.6.5 of this Part, cannot be less than 0.2 mg/L, measured as free chlorine, for more than four (4) hours.

4. The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine or chlorine dioxide as specified in § 1.6.5 of this Part, cannot be undetectable in more than five (5) percent of the samples each month, for any two (2) consecutive months that the PWS serves water to the public.

a. Water in the distribution system with a heterotrophic bacteria concentration less than or equal to 500/ml measured as heterotrophic plate count (HPC) as specified in § 1.6.5 of this Part, is deemed to have a detectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value "V" in the following formula cannot exceed 5 percent in one (1) month for any two (2) consecutive months:

Click here to view image

Where:

a = Number of instances where the residual disinfectant concentration is measured;

b = Number of instances where the residual disinfectant concentration is not measured but the heterotrophic bacteria plate count (HPC) is measured;

c = Number of instances where the residual disinfectant concentration is measured but not detected and no HPC is measured;

d = Number of instances where the residual disinfectant concentration is measured but not detected and where the HPC is >500/ml; and

e = Number of instances where the residual disinfectant concentration is not measured and HPC is >500/ml.

F. Disinfection Requirements for PWS Which Provide Filtration. Each PWS that provides filtration treatment must provide disinfection treatment as follows:

1. The disinfection treatment must be sufficient to ensure that the total treatment processes of that system achieve at least 99.9 percent (3-log) inactivation and/or removal of Giardia lamblia cysts and at least 99.99 percent (4-log) inactivation and/or removal of viruses as determined by the Director every day the PWS serves water to the public, except any one (1) day each month. At least 0.5 log (68.4 percent) must be achieved by chemical disinfection. Each day a PWS serves water to the public, the PWS must calculate the CT value(s) from the PWS's treatment parameters, using the procedure specified in § 1.6.6(A)(3) and (4) of this Part and determine whether this value is sufficient to achieve the specified inactivation rates for Giardia lamblia cysts and viruses. In lieu of Tables 1.1-1.6, 2.1, and 3.1 in § 1.6.8 of this Part for 99.9 percent inactivation, Tables C-1 through C-13 of the 1999 EPA Disinfection Profiling and Benchmarking Guidance Manual may be used for different percent inactivation requirements such as 68.4 percent (0.5-log).

a. If a PWS uses a disinfectant other than chlorine, the PWS may demonstrate to the Director, through the use of a protocol approved by the Director for on-site disinfection challenge studies or other information satisfactory to the Director, that the CT99.9 values other than those specified in Tables 2.1 and 3.1 in § 1.6.8 of this Part or other operational parameters are adequate to demonstrate that the PWS is achieving minimum inactivation rates required by § 1.6.3(F)(1) of this Part.

2. The disinfection system must have either:

b. Automatic shut-off of delivery of water to the distribution system whenever there is less than 0.2 mg/L of residual disinfectant concentration in the water.

(1) If the Director determines that automatic shut-off would cause unreasonable risk to health or interfere with fire protection, the system must comply with § 1.6.3(F)(2)(a) of this Part.

4. The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in § 1.6.5 of this Part, cannot be undetectable in more than five (5) percent of the samples each month, for any two (2) consecutive months that the PWS serves water to the public.

a. Water in the distribution system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured as heterotrophic plate count (HPC) as specified in § 1.6.5 of this Part, is deemed to have a detectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value of "V" cannot exceed five (5) percent in one (1) month for any two (2) consecutive months. [See formula in § 1.6.3(E)(4) of this Part].

G. Disinfection Profiling and Benchmarking

1. A § 1.6 community or non-transient, non-community PWS that serves fewer than ten thousand (10,000) people must develop a disinfection profile, a graphical representation of a PWS's level of Giardia lamblia or virus inactivation measured during the course of a year, under the provisions of §§ 1.6.3(G)(1), (2) and (3) of this Part, unless the Director determines that it is unnecessary. At the Director's discretion, a § 1.6 PWS that serves at least ten thousand (10,000) people may also be required to develop a disinfection profile. If the Director requires a PWS serving at least ten thousand (10,000) people to develop a profile, the Director shall specify procedures for developing that profile.

a. The Director may only determine that a PWS's profile is unnecessary if a PWS's TTHM and HAA5 levels are below 0.064 mg/L and 0.048 mg/L, respectively.

b. If TTHM and HAA5 levels are greater than or equal to 0.064mg/L or greater than or equal to 0.048 mg/L, respectively, the PWS must comply with § 1.6.3(G)(2)(a) of this Part.

c. To determine these levels, TTHM and HAA5 samples must be collected during the month with the warmest water temperature, and at the point of maximum residence time in the distribution system.

2. Disinfection Profile Criteria

a. Any § 1.6 PWS serving fewer than ten thousand (10,000) people that meets the criteria in § 1.6.3(G)(1)(b) of this Part must develop a disinfection profile of its disinfection practice for a period of up to one (1) year. The Director may approve the use of a more representative data set for disinfection profiling than the data set required under §§ 1.6.3(G)(2)(a)((1)) and (G)(3) of this Part.

(1) PWS must collect data for several parameters from the plant, specified in § 1.6.3(G)(2)(a)((1))((AA)) through ((DD)) of this Part, once per week on the same calendar day over twelve (12) consecutive calendar months to determine the total logs of inactivation for each day of operation, based on the CT99.9 values in Tables 1.1-1.6, 2.1 and 3.1 in § 1.6.8 of this Part, as appropriate, through the entire treatment plant. PWS serving between five hundred (500) and nine hundred ninety-nine (9,999) persons must begin to collect data no later than July 1, 2003. PWS serving fewer than five hundred (500) persons must begin to collect data no later than January 1, 2004. The PWS must monitor the parameters listed in §§ 1.6.3(G)(2)(a)((1))((AA)) through ((DD)) of this Part, necessary to determine the total inactivation ratio, using analytical methods in §§ 1.6.5 and 1.21 of this Part.

(AA) The temperature of the disinfected water at each residual disinfectant concentration sampling point during peak hourly flow;

(BB) If the PWS uses chlorine, the pH of the disinfected water at each chlorine residual disinfectant concentration sampling point during peak hourly flow;

(CC) The disinfectant contact time(s) ("T") during peak hourly flow; and

(DD) The residual disinfectant concentration(s) ("C") of the water before or at the first customer and prior to each additional point of disinfection during peak hourly flow.

(2) PWS must use this data to calculate the inactivation ratios as discussed in §§ 1.6.6(A)(4)(a) and (b) of this Part. As a minimum, the PWS with a single point of disinfectant application prior to entrance to the distribution system must calculate the inactivation ratio as discussed in § 1.6.6(A)(4)(a) of this Part. A PWS with more than one (1) point of disinfectant application or measures disinfectant residuals at more than one (1) location must calculate the inactivation ratio as discussed in § 1.6.6(A)(4)(b) of this Part for each disinfection segment.

(3) Weekly log inactivations are calculated by multiplying the CTcalc/CT99.9 ratio across the entire treatment train by 3.

(4) PWS must use these weekly log inactivations to develop a disinfection profile as specified in § 1.6.3(G)(3)(a) of this Part.

3. Developing a Disinfection Profile

a. Each log inactivation serves as a data point in your disinfection profile. PWS serving fewer than ten thousand (10,000) people will have obtained fifty-two (52) measurements (one (1) for every week of the year). The PWS and the Director will evaluate how microbial inactivation varied over the course of the year by looking at all fifty-two (52) measurements (the Disinfection Profile). PWS must retain the Disinfection Profile data in graphic form, such as a spreadsheet, which must be available for review by the Director as part of a sanitary survey. PWS must use this data to calculate a benchmark if the PWS is considering changes to disinfection practices.

b. A PWS that uses chloramines, ozone or chlorine dioxide for primary disinfection must also calculate the logs of inactivation for viruses and develop an additional disinfection profile for viruses using a method approved by the Director.

4. Disinfection Benchmark

a. A § 1.6 PWS serving less than ten thousand (10,000) people that is required to develop a disinfection profile under the provisions of § 1.6.3(G)(1) of this Part, must develop a Disinfection Benchmark as described in §§ 1.6.3(G)(4)(c) and (d) of this Part and provide the benchmark to the Director if the PWS decides to make a significant change to its disinfection practice. A § 1.6 PWS serving at least ten thousand (10,000) people that is required to develop a disinfection profile under the provisions of § 1.6.3(G)(1) of this Part, must develop a Disinfection Benchmark using procedures specified by the Director if the PWS decides to make a significant change to its disinfection practice. All PWS must consult with the Director for approval prior to making such changes. Significant changes to disinfection practice are:

(1) Changes to the point of disinfection;

(2) Changes to the disinfectant(s) used in the treatment plant;

(3) Changes to the disinfection process; and

(4) Any other modification identified by the Director.

b. PWS must submit the following information to the Director as part of the consultation and approval process:

(1) A description of the proposed change;

(2) The disinfection profile for Giardia lamblia (and, if necessary, viruses) and disinfection benchmark;

(3) An analysis of how the proposed change will affect the current levels of disinfection; and

(4) Any additional information requested by the Director.

c. Any PWS that is modifying its disinfection practice must calculate its disinfection benchmark using the procedures specified in §§ 1.6.3(G)(4)(c)((1)) through ((2)) of this Part.

(1) For one (1) year of profiling data collected weekly and calculated under §§ 1.6.3(G)(2) and (3) of this Part, the PWS must determine the lowest average monthly Giardia lamblia inactivation for one (1) year. The PWS must determine the average Giardia lamblia inactivation for each calendar month by dividing the sum of all Giardia lamblia inactivations for that month by the number of values calculated for that month.

(2) The disinfection benchmark value is the lowest monthly average value out of twelve (12) values of Giardia lamblia inactivation in one (1) year of profiling data.

d. A PWS that uses chloramines, ozone or chlorine dioxide for primary disinfection must calculate the disinfection benchmark from the data collected for viruses to develop the disinfection profile in addition to the Giardia lamblia disinfection benchmark calculated under § 1.6.3(G)(4)(c) of this Part. This viral benchmark must be approved by the Director and must be calculated in the same manner used to calculate the Giardia lamblia disinfection benchmark in § 1.6.3(G)(4)(c) of this Part.

1.6.4Filtration

A. A § 1.6 PWS that does not meet all of the criteria in § 1.6.2 of this Part for avoiding filtration, must provide treatment consisting of both disinfection, as specified in § 1.6.3(F) of this Part and filtration treatment which complies with the requirements of § 1.6.4 of this Part within eighteen (18) months of the failure to meet any one (1) of the criteria for avoiding filtration. Failure to meet any requirement of this Section by the date specified in § 1.6.4(A) of this Part, shall constitute a treatment technique violation.

B. Conventional Filtration Treatment or Direct Filtration:

1. PWS that use conventional filtration or direct filtration that do not meet all of the criteria listed in 40 C.F.R. § 141.71 for avoiding filtration must meet the turbidity requirements listed in §§ 1.6.4(B)(1)(a), (b) and (c) of this Part below:

a. The turbidity level of representative samples of a PWS's filtered water must be less than or equal to 0.3 NTU in at least ninety-five (95) percent of the measurements taken each month, measured as specified in §§ 1.6.5 and 1.6.7 of this Part. Monthly reporting must be completed according to § 1.6.8 of this Part.

b. The turbidity level of representative samples of a PWS's filtered water must at no time exceed one (1) NTU, measured as specified in §§ 1.6.5 and 1.6.7 of this Part. Monthly reporting must be completed according to § 1.6.8 of this Part.

c. A PWS that uses lime softening may acidify representative combined filter effluent turbidity samples prior to analysis using a protocol approved by the Director.

C. Slow Sand Filtration

1. For PWS using slow sand filtration, the turbidity level of representative samples of a PWS's filtered water must be less than or equal to one (1) NTU in at least ninety-five percent (95%) of the measurements taken each month, measured as specified in § 1.6.5 of this Part.

2. The turbidity level of representative samples of a PWS's filtered water must at no time exceed five (5) NTU measured as specified in § 1.6.5 of this Part.

D. Diatomaceous Earth Filtration

1. For PWS using diatomaceous earth filtration, the turbidity level of representative samples of a PWS's filtered water must be less than or equal to one (1) NTU in at least ninety-five percent (95%) of the measurements taken each month, measured as specified in § 1.6.5 of this Part.

2. The turbidity level of representative samples of a PWS's filtered water must at no time exceed five (5) NTU, measured as specified in § 1.6.5 of this Part.

E. Other Filtration Technologies. A PWS may use a filtration technology not listed in 40 C.F.R. § 141.73 or § 1.6.4 of this Part, if it demonstrates to the Director, using pilot plant studies or other means, that the alternative filtration technology, in combination with disinfection treatment that meets the requirements of 40 C.F.R. §§ 141.72 and 141.73, consistently achieves ninety-nine percent (99%) removal of Cryptosporidium oocysts, 99.9 percent removal and/or inactivation of Giardia lamblia cysts and 99.99 percent removal and/or inactivation of viruses. Upon completion of the demonstration, the Director will determine the 95^th percentile turbidity value (not to exceed one (1) NTU) and the maximum turbidity value (not to exceed five (5) NTU) based on the demonstration.

1.6.5Analytical Monitoring Requirements

A. Only the analytical method(s) specified in this Section, or otherwise approved by the Director, may be used to demonstrate compliance with the requirements of §§ 1.6.2, 1.6.3, or 1.6.4 of this Part.

1. Measurements for pH, temperature, turbidity, and residual disinfectant concentrations must be conducted by a party approved by the Director.

2. Measurements for total coliforms, fecal coliforms and HPC must be conducted by a laboratory certified by the Director or EPA to do such analysis.

B. The following procedures shall be performed in accordance with the methods listed.

1. Fecal Coliform/E. Coli Concentration Method, as set forth in § 1.21 of this Part.

2. Total Coliform Concentration, as set forth in § 1.21 of this Part.

3. Heterotrophic Plate Count, as set forth in § 1.21 of this Part.

4. Turbidity, as set forth in § 1.21 of this Part.

5. Residual Disinfectant Concentration, as set forth in § 1.21 of this Part.

6. Temperature, as set forth in § 1.21 of this Part.

7. pH, as set forth in § 1.21 of this Part.

8. Minimal Medium ONPG-MUG method for simultaneous enumeration of total coliform and E. Coli as set forth in § 1.21 of this Part.

9. Indigo Method for determination of Ozone in water, as set forth in § 1.21 of this Part.

1.6.6Monitoring Requirements for PWSs That Do Not Provide Filtration

A. A PWS that uses a surface water source and does not provide filtration treatment must begin monitoring, as specified in this Section, unless the Director has determined that filtration is required in writing, in which case the Director may specify alternative monitoring requirements, until filtration is in place. A PWS that uses a groundwater source under the direct influence of surface water and does not provide filtration treatment must begin monitoring as specified in this Section six (6) months after the Director determines that the groundwater source is under the direct influence of surface water, unless the Director has determined that filtration is required in writing.

1. Fecal coliform or total coliform density measurements, as required by § 1.6.2(E) of this Part, must be performed on representative source water samples immediately prior to the first or only point of disinfectant application. The PWS must sample for fecal or total coliforms at the following minimum frequency each week the PWS serves water to the public:

PWS Size (Persons Served)	Samples/Week (samples must be taken on separate days)
<500	1
501 to 3,300	2
3,301 to 10,000	3
10,001 to 25,000	4
&>25,000	5

a. Also, one (1) fecal or total coliform density measurement must be made every day the PWS serves water to the public and the turbidity of the source water exceeds 1 NTU (these samples count toward the weekly coliform sampling requirement,) unless the Director determines that the PWS for logistical reasons outside the PWS's control cannot have the sample analyzed within thirty (30) hours of collection.

2. Turbidity measurements as required by § 1.6.2(D)(3) of this Part must be performed on representative grab samples of source water immediately prior to the first or only point of disinfectant application every four (4) hours (or more frequently) that the PWS serves water to the public. A PWS may substitute continuous turbidity monitoring for grab sample monitoring if it validates the continuous measurement for accuracy on a regular basis using procedures specified by the manufacturer, but no less frequently than every three (3) months.

3. The total inactivation ratio for each day that the PWS is in operation must be determined based on the CT99.9 values in Tables 1.1-1.6, 2.1 and 3.1 in § 1.6.8 of this Part, as appropriate. The parameters necessary to determine the total inactivation ratio must be monitored as follows:

a. The temperature of the disinfected water must be measured at least once per day at each residual disinfectant concentration sampling point during peak hourly flow.

b. If the PWS uses chlorine, the pH of the disinfected water must be measured at least once per day at each chlorine residual disinfectant concentration sampling point during peak hourly flow.

c. The disinfectant contact time(s) ("T") must be determined for each day during peak hourly flow.

d. The residual disinfectant concentration(s) ("C") of the water before or at the first customer must be measured each day during peak hourly flow.

e. If a PWS uses a disinfectant other than chlorine, the PWS may demonstrate to the Director, through the use of a protocol approved by the Director, for on-site disinfection challenge studies or other information satisfactory to the Director that CT99.9 values other than those specified in Tables 2.1 and 3.1 in § 1.6.8 of this Part or other operational parameters are adequate to demonstrate that the PWS is achieving the minimum inactivation rates required by § 1.6.3(E)(1) of this Part.

4. The total inactivation ratio must be calculated as follows:

a. If the PWS uses only one (1) point of disinfectant application, the PWS may determine the total inactivation ratio based on either of the following two (2) methods:

(1) One (1) inactivation ratio (CTcalc/CT99.9) is determined before or at the first customer during peak hourly flow and if the CTcalc/CT99.9 is greater than 1.0, the 99.9 percent Giardia lamblia inactivation requirement has been achieved; OR

(2) Successive CTcalc/CT99.9 values representing sequential inactivation ratios are determined between the point of disinfectant application and a point before or at the first customer during peak hourly flow. Under this alternative, the following method must be used to calculate the total inactivation ratio:

(AA) Determine (CTcalc/CT99.9) for each sequence

(BB) Add the (CTcalc/CT99.9) values together (the sum of all CTcalc/CT99.9)

(CC) If the sum of (CTcalc/CT99.9) is greater than 1.0, then the 99.9 percent Giardia lamblia inactivation requirement has been achieved.

b. If the PWS uses more than one (1) point of disinfectant application before or at the first customer, the PWS must determine the CT value of each disinfection sequence immediately prior to the next point of disinfectant application during peak hourly flow. The CTcalc/CT99.9 value of each sequence and the sum of CTcalc/CT99.9 must be calculated using the method in § 1.6.6(A)(4)(a)((2)) of this Part to determine if the PWS is in compliance with § 1.6.3(E) of this Part.

c. Although not required, the total percent inactivation for a PWS with one (1) or more points of residual disinfectant concentration monitoring may be calculated by solving the following equation: Percent inactivation = 100-(100/10Z), where Z = 3 x the sum of (CTcalc/CT99.9).

5. The residual disinfectant concentration of the water entering the distribution system must be monitored continuously using analytical methods specified in § 1.21 of this Part, and the lowest value must be recorded each day. In the event of system monitoring failure, grab sampling may be conducted every four (4) hours, for no more than five (5) working days.

a. PWS serving three thousand three hundred (3,300) or fewer persons may take grab samples in lieu of continuous monitoring on an ongoing basis at the frequencies prescribed below:

PWS Size by Population	Samples/day (The day's samples cannot be taken at the same time. The sampling intervals are subject to the Director's review and approval)
<501	1
501 to 1,000	2
1,001 to 2,500	3
2,501 to 3,300	4

b. If at any time the residual disinfectant concentration falls below 0.2 mg/L in a PWS using grab sampling in lieu of continuous monitoring, the PWS must take a grab sample every four (4) hours until the residual concentration is equal to or greater than 0.2 mg/L.

6. The residual disinfectant concentration must be measured at least at the same points in the distribution system and at the same time as total coliforms are sampled, as specified in §§ 1.16.4 and 1.17.1 of this Part. The Director may allow a PWS which uses both a surface water source or a groundwater source under direct influence of surface water, and a groundwater source to take disinfectant residual samples at points other than the total coliform sampling points, if the Director determines that such points are more representative of treated (disinfected) water quality within the distribution system.

a. Heterotrophic bacteria, measured as HPC as specified in § 1.6.5(B)(3) of this Part, may be measured in lieu of residual disinfectant concentration except as specified in § 1.8.5(C)(1) of this Part.

1.6.7Monitoring Requirements for PWSs Using Filtration Treatment

A. A PWS that uses a surface water source or a groundwater source under the influence of surface water and provides filtration treatment must monitor in accordance with this Section:

1. Turbidity

a. Representative Filtered Effluent Turbidity Requirements

(1) Turbidity measurements as required by § 1.6.4 of this Part must be performed on representative samples of the PWS's filtered water every four (4) hours (or more frequently) that the PWS serves water to the public. A PWS may substitute continuous turbidity monitoring for grab sample monitoring if it validates the continuous measurement for accuracy on a regular basis, using procedures specified by the manufacturer, but no less frequently than every three (3) months.

(2) For any PWS using slow sand filtration or filtration treatment other than conventional treatment, direct filtration or diatomaceous earth filtration, the Director may reduce the sampling frequency to once per day if it determines that less frequent monitoring is sufficient to indicate effective filtration performance.

(3) For PWS serving five hundred (500) or fewer persons, the Director may reduce the turbidity sampling frequency to once per day, regardless of the type of filtration treatment used, if the Director determines that less frequent monitoring is sufficient to indicate effective filtration performance.

b. Individual Filter Turbidity Requirements

(1) § 1.6 PWS that use conventional or direct filtration must conduct continuous monitoring of turbidity for each individual filter in the system. The following requirements apply to continuous turbidity monitoring:

(AA) Continuous monitoring must be conducted using an approved method in § 1.6.5 of this Part;

(BB) Calibration of turbidimeters must be conducted using procedures specified by the manufacturer, but no less frequently than every three (3) months;

(CC) Results of turbidity monitoring must be recorded at least every fifteen (15) minutes; and

(DD) Monthly reporting must be completed and records must be maintained according to § 1.6.8 of this Part.

(2) If there is a failure in the continuous turbidity monitoring equipment, the PWS must conduct grab sampling every four (4) hours in lieu of continuous monitoring until the turbidimeter is back on-line. PWS serving at least ten thousand (10,000) people have no more than five (5) working days, following equipment failure, and PWS serving fewer than ten thousand (10,000) people have no more than fourteen (14) total days, following equipment failure, to resume continuous monitoring before a violation is incurred.

(3) For PWS serving fewer than ten thousand (10,000) people, PWS that only consist of two (2) or fewer filters may conduct continuous monitoring of combined filter effluent turbidity in lieu of individual filter effluent turbidity monitoring. Continuous monitoring must meet the same requirements set forth in §§ 1.6.7(A)(1)(b)((1)) and ((2)) of this Part.

2. The total inactivation ratio must be calculated as indicated in § 1.6.6(A)(4) of this Part.

3. The residual disinfectant concentration of the water entering the distribution system, and throughout the distribution system, must be monitored as indicated in §§ 1.6.6(A)(5) and (6) of this Part.

1.6.8Reporting and Record Keeping Requirements

A. A PWS that uses a surface water source and does not provide filtration treatment must report the following information monthly to the Director unless the Director has determined that filtration is required in writing, in which case the Director may specify alternate reporting requirements as appropriate until filtration is in place. A PWS that uses a groundwater source under the direct influence of surface water and does not provide filtration treatment must report monthly to the Director, the following information beginning no later than six (6) months after the Director determines that the groundwater source is under the direct influence of surface water:

1. Source water quality information must be reported to the Director within ten (10) days after the end of each month the PWS serves water to the public. Information that must be reported:

a. The cumulative number of months for which results are reported.

b. The number of fecal and/or total coliform samples, whichever are analyzed during the month (if a PWS monitors for both, only fecal coliforms must be reported), the dates of sample collection and the dates when the turbidity level exceeded one (1) NTU.

c. The number of samples during the month that had equal to or less than 20/100 ml fecal coliforms and/or equal to or less than 100/100 ml total coliforms, whichever are analyzed.

d. The cumulative number of fecal or total coliform samples, whichever are analyzed during the previous six (6) months the PWS served water to the public.

e. The cumulative number of samples that had equal to or less than 20/100 ml fecal coliforms or equal to or less than 100/100 ml total coliforms, whichever are analyzed during the previous six (6) months the PWS served water to the public.

f. The percentage of samples that had equal to or less than 20/100 ml fecal coliforms or equal to or less than 100/100 ml total coliforms, whichever are analyzed during the previous six (6) months the PWS served water to the public.

g. The maximum turbidity level measured during the month, the date(s) of occurrence for any measurement(s) which exceeded five (5) NTU, and the date(s) the occurrence(s) was reported to the Director.

h. For the first twelve (12) months of record-keeping, the dates and cumulative number of events during which the turbidity exceeded five (5) NTU and after one (1) year of record keeping for turbidity measurements, the dates and cumulative number of events during which the turbidity exceeded five (5) NTU in the previous twelve (12) months the PWS served water to the public.

i. For the first one hundred twenty (120) months of record-keeping, the dates and cumulative number of events during which the turbidity exceeded five (5) NTU and after ten (10) years of record keeping for turbidity measurements, the dates and cumulative number of events during which the turbidity exceeded five (5) NTU in the previous one hundred twenty (120) months they PWS service water to the public.

2. Disinfection information must be reported to the Director within ten (10) days after the end of each month the PWS serves water to the public. Information that must be reported:

a. For each day, the lowest measurement of residual disinfectant concentration in mg/L in water entering the distribution system.

b. The date and duration of each period when the residual disinfectant concentration in water entering the distribution system fell below 0.2 mg/L and when the Director was notified of the occurrence.

c. The daily residual disinfectant concentration(s) (in mg/L) and disinfectant contact time(s) (in minutes) used for calculating the CT value(s).

d. If chlorine is used, the daily measurement(s) of pH of disinfected water following each point of chlorine disinfection.

e. The daily measurement(s) of water temperature in degrees centigrade following each point of disinfection.

f. The daily CTcalc and CTcalc/CT99.9 values for each disinfectant measurement or sequence and the sum of all CTcalc/CT99.9 values (CTcalc/CT99.9) before or at the first customer.

g. The daily determination of whether disinfection achieves adequate Giardia cyst and virus inactivation, i.e. whether (CTcalc/ CT99.9) is at least 1.0 or where disinfectants other than chlorine are used, other indicator conditions that the Director determines are appropriate, are met.

h. The following information on the samples taken in the distribution system in conjunction with total coliform monitoring specified in § 1.6.3 of this Part.

(1) Number of instances where the residual disinfectant concentration is measured;

(2) Number of instances where the residual disinfectant concentration is not measured but HPC is measured;

(3) Number of instances where the residual disinfectant concentration is measured, but not detected and no HPC is measured;

(4) Number of instances where the residual disinfectant concentration is detected and where HPC is >500/ml;

(5) Number of instances where the residual disinfectant concentration is not measured and HPC is >500/ml;

(6) For the current and previous month the PWS served water to the public, the value of "V", as defined in § 1.6.3(E) of this Part.

i. A PWS need not report the data listed in §§ 1.6.8(A)(2)(a) and (c) through (f) of this Part, if all data listed in §§ 1.6.8(A)(2)(a) through (h) of this Part, remain on file at the PWS and the Director determines that:

(1) The PWS has submitted to the Director all the information required for at least twelve (12) months; and

(2) The Director has determined that the PWS is not required to provide filtration treatment.

3. No later than October 10 of each year, each PWS must provide to the Director a report which summarizes its compliance with all watershed control program requirements specified in § 1.6.2(E)(2) of this Part.

4. A report on the on-site inspection conducted during that year as specified in § 1.6.2(E)(3) of this Part.

5. Each PWS, upon discovering that a waterborne disease outbreak potentially attributable to that PWS has occurred, must report that occurrence to the Director as soon as possible, but no later than the end of the next business day.

a. If at any time the turbidity exceeds five (5) NTU, the PWS must consult with the Director as soon as practical, but no later than twenty-four (24) hours after the exceedance is known, in accordance with the public notification requirements under § 1.16.6 of this Part.

b. If at any time the residual falls below 0.2 mg/L in the water entering the distribution system, the PWS must notify the Director as soon as possible, but no later than by the end of the next business day. The PWS must notify the Director by the end of the next business day whether or not the residual was restored to at least 0.2 mg/L within four (4) hours.

B. § 1.6 PWS that provide filtration treatment must report monthly to the Director the following information in §§ 1.6.8(B)(1) through (4) of this Part, unless otherwise stated.

1. Turbidity requirements: Turbidity measurements as required by §§ 1.6.4 and 1.6.7 of this Part, must be reported within ten (10) days after the end of each month the PWS serves water to the public. Information that must be reported includes:

a. The total number of filtered water turbidity measurements taken during the month.

b. The number and percentage of filtered water turbidity measurements taken during the month which are less than or equal to the turbidity limits specified in § 1.6.4 of this Part, for the filtration technology being used.

c. The date and value of any turbidity measurements taken during the month which exceed the maximum allowable turbidity specified in § 1.6.4 of this Part.

2. Individual filter effluent reporting requirements (conventional and direct filtration systems only). PWS must maintain the results of individual filter monitoring taken under § 1.6.7(A)(1)(b) of this Part, for at least three (3) years. PWS must report that they have conducted individual filter turbidity monitoring under § 1.6.7(A)(1)(b) of this Part, within ten (10) days after the end of each month the PWS serves water to the public. PWS must report individual filter turbidity measurement results taken under § 1.6.7(A)(1)(b) of this Part, within ten (10) days after the end of each month the PWS serves water to the public only if measurements demonstrate one (1) or more of the conditions in § 1.6.8(B)(4) of this Part.

3. Disinfection information must be reported to the Director within ten (10) days after the end of each month and must include all items specified in §§ 1.6.8(A)(2)(a) through (h) and 1.6.8(A)(5) of this Part.

a. Disinfection Profiling: By July 1, 2003, PWS serving 500-9,999 people and by January 1, 2004, PWS serving fewer than 500 people must report the results of optional monitoring which shows TTHM levels below 0.064 mg/L and HAA5 levels below 0.048 mg/L (only if the PWS wishes to forgo profiling) or PWS must report that they have begun disinfection profiling. If profiling is required by the Director for PWS serving at least 10,000 people, the necessary reporting requirements will be specified by the Director. Records of the profile, if required, must be kept indefinitely including raw data and analysis and made available to the Director as part of a sanitary survey.

b. Disinfection Benchmarking: If a PWS serving fewer than 10,000 people was required to produce a disinfection profile and is considering a significant change to its disinfection practices, they must report a description of the proposed change in disinfection, a disinfection profile for Giardia lamblia (and, if necessary, viruses) and disinfection benchmark, and an analysis of how the proposed change will affect the current levels of disinfection. If benchmarking is required by the Director for PWS serving at least 10,000 people, the necessary reporting requirements will be specified by the Director. Records of the benchmark must be kept indefinitely including raw data and analysis and made available to the Director as part of a sanitary survey.

4. Individual filter effluent follow-up actions: For all PWS, reporting to the Director is required by the 10th of the following month for exceedance listed in §§ 1.6.8(B)(4)(a) through (d) of this Part, unless otherwise stated. PWS that use lime softening may apply to the Director for alternative exceedance levels for the levels specified in §§ 1.6.8(B)(4)(a) through (d) of this Part, if they can demonstrate that higher turbidity levels in individual filters are due to lime carryover only and not due to degraded filter performance.

a. If the individual filter effluent turbidity (or for PWS serving fewer than 10,000, the turbidity of combined filter effluent (CFE) for PWSs with two (2) filters that monitor CFE in lieu of individual filters) exceeded 1.0 NTU in two (2) consecutive measurements taken fifteen (15) minutes apart, the PWS must report the filter number, the turbidity measurement, the date(s) on which the exceedance occurred and the cause (if known) for the exceedance. In addition, PWS serving at least 10,000 people must either produce a filter profile for the filter within seven (7) days of the exceedance (if the PWS is not able to identify an obvious reason for the abnormal filter performance) and report that the profile has been produced or report the obvious reason for the exceedance.

b. For PWS serving at least 10,000 people, if the individual filter effluent turbidity exceeded 0.5 NTU in two (2) consecutive measurements taken fifteen (15) minutes apart at the end of the first four (4) hours of continuous filter operation after the filter has been backwashed or otherwise taken offline, the PWS must report the filter number, the turbidity, and the date(s) on which the exceedance occurred. In addition, the PWS must either produce a filter profile for the filter within seven (7) days of the exceedance (if the PWS is not able to identify an obvious reason for the abnormal filter performance) and report that the profile has been produced or report the obvious reason for the exceedance.

c. If the individual filter effluent turbidity (or for PWS serving fewer than 10,000, the CFE turbidity of PWSs with two (2) filters that monitor CFE in lieu of individual filters) exceeded 1.0 NTU in two (2) consecutive 15-minute readings for three (3) consecutive months, the PWS must report the filter number, the turbidity measurement, and the date(s) on which the exceedance occurred. In addition, the PWS must conduct a self-assessment of the filter(s) within fourteen (14) days of the exceedance unless a CPE as specified in § 1.6.8(B)(4)(d) of this Part, was required. PWS with two (2) filters that monitor combined filter effluent in lieu of individual filters must conduct a self-assessment on both filters. The PWS must report the date the filter self-assessment was triggered and the date it was completed by the 10th of the following month or fourteen (14) days after the self-assessment was triggered only if the self-assessment was triggered during the last four (4) days of the month. The self-assessment must consist of at least the following components:

(1) Assessment of filter performance;

(2) Development of a filter profile;

(3) Identification and prioritization of factors limiting filter performance;

(4) Assessment of the applicability of corrections; and

(5) Preparation of a filter self-assessment report.

d. If the individual filter effluent turbidity (or for PWS serving fewer than 10,000, the CFE for PWS with two (2) filters that monitor combined filter effluent in lieu of individual filters) exceeded 2.0 NTU in two (2) consecutive recordings fifteen (15) minutes apart at the same filter for two (2) consecutive months, the PWS must report the filter number, the turbidity measurement, and the date(s) on which the exceedance occurred. In addition, the PWS must arrange to have a comprehensive performance evaluation (CPE) conducted by the Director or a third party approved by Director not later than thirty (30) days (sixty (60) days for PWS serving fewer than 10,000) following the day the filter exceeded 2.0 NTU in two (2) consecutive measurements for the second straight month. If a CPE has been completed by the Director or a third party approved by the Director within the 12 prior months or the PWS and Director are jointly participating in an ongoing Comprehensive Technical Assistance (CTA) project at the PWS, a new CPE is not required. If conducted, a CPE must be completed and submitted to the Director no later than ninety (90) days (120 days for PWS serving fewer than 10,000) following the day the filter exceeded 2.0 NTU in two (2) consecutive measurements for the second straight month. The PWS must report by the 10th of the following month that a CPE was required and the date it was triggered.

5. The disinfection information must be reported as indicated in § 1.6.8(A)(2) of this Part.

C. For all filtration technologies, a § 1.6 PWS that exceeds the maximum turbidity as specified in § 1.6.4 of this Part, must inform the Director within twenty-four (24) hours.

D. Recycle Provisions:

1. Reporting. A PWS must notify the Director if the PWS recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes. This notification must include, at a minimum, the information specified in §§ 1.6.8(D)(1)(a) and (b) of this Part.

a. A plant schematic showing the origin of all flows which are recycled (including, but not limited to, spent filter backwash water, thickener supernatant and liquids from dewatering processes), the hydraulic conveyance used to transport them, and the location where they are re-introduced back into the treatment plant.

b. Typical recycle flow in gallons per minute (gpm) the highest observed plant flow experienced in the previous year (gpm), design flow for the treatment plant (gpm), and Director-approved operating capacity for the plant where the Director has made such determinations.

2. Recordkeeping. The PWS must collect and retain on file recycle flow information specified in §§ 1.6.8(D)(2)(a) through (f) of this Part, for review and evaluation by the Director.

a. Copy of the recycle notification and information submitted to the Director under § 1.6.8(D)(1) of this Part.

b. List of all recycle flows and the frequency with which they are returned.

c. Average and maximum backwash flow rate through the filters and the average and maximum duration of the filter backwash process in minutes.

d. Typical filter run length and a written summary of how filter run length is determined.

e. The type of treatment provided for the recycle flow.

f. Data on the physical dimensions of the equalization and/or treatment units, typical and maximum hydraulic loading rates, type of treatment chemicals used and average dose and frequency of use, and frequency at which solids are removed, if applicable.

Table 1.1 CT values (CT99.9) for 99.9 percent inactivation of giardia lamblia cysts by free chlorine at 0.5°C or lower¹
Residual (mg/L)	pH
	<6.0	6.5	7.0	7.5	8.0	8.5	<9.0
<0.4	137	163	195	237	277	329	390
0.6	141	168	200	239	286	342	407
0.8	145	172	205	246	295	354	422
1.0	148	176	210	253	304	365	437
1.2	152	180	215	259	313	376	451
1.4	155	184	221	266	321	387	464
1.6	157	189	226	273	329	397	477
1.8	162	193	231	279	338	407	489
2.0	165	197	236	286	346	417	500
2.2	169	201	242	297	353	426	511
2.4	172	205	247	298	361	435	522
2.6	175	209	252	304	368	444	533
2.8	178	213	257	310	375	452	543
3.0	181	217	261	316	382	460	552
¹ These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature and at the higher pH.

Table 1.2 CT values (CT99.9) for 99.9 percent inactivation of giardia lamblia cysts by free chlorine at 0.5°C¹
Free Residual (mg/L)	pH
	<6.0	6.5	7.0	7.5	8.0	8.5	<9.0
<0.4	97	117	139	166	198	236	279
0.6	100	120	143	171	204	244	291
0.8	103	122	146	175	210	252	301
1.0	105	125	149	179	216	260	312
1.2	107	127	152	183	221	267	320
1.4	109	130	155	187	227	274	329
1.6	111	132	158	192	232	281	337
1.8	114	135	162	196	238	287	345
2.0	116	138	165	200	243	294	353
2.2	118	140	169	204	248	300	361
2.4	120	143	172	209	253	306	368
2.6	122	146	175	213	258	312	375
2.8	124	148	178	217	263	318	382
3.0	126	151	182	221	268	324	389
¹ These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature and at the higher pH.

Table 1.3 CT values (CT99.9) for 99.9 percent inactivation of giardia lamblia cysts by free chlorine at 10.0°C¹
Free Residual (mg/L)	pH
	<6.0	6.5	7.0	7.5	8.0	8.5	<9.0
<0.4	73	88	104	125	149	177	209
0.6	75	90	107	128	153	183	218
0.8	78	92	110	131	158	189	226
1.0	79	94	112	134	162	195	234
1.2	80	95	114	137	166	200	240
1.4	82	98	116	140	170	206	247
1.6	83	99	119	144	174	211	253
1.8	86	101	122	147	179	215	259
2.0	87	104	124	150	182	221	265
2.2	89	105	127	153	186	225	271
2.4	90	107	129	157	190	230	276
2.6	92	110	131	160	194	234	281
2.8	93	111	134	163	197	239	287
3.0	95	113	137	166	201	243	292
¹ These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature and at the higher pH.

Table 1.4 CT values (CT99.9) for 99.9 percent inactivation of giardia lamblia cysts by free chlorine at 15.0°C¹
Free Residual (mg/L)	pH
	<6.0	6.5	7.0	7.5	8.0	8.5	<9.0
<0.4	49	59	70	83	99	118	140
0.6	50	60	72	86	102	122	146
0.8	52	61	73	88	105	126	151
1.0	53	63	75	90	108	130	156
1.2	54	64	76	92	111	134	160
1.4	55	65	78	94	114	137	165
1.6	56	66	79	96	116	141	169
1.8	57	68	81	98	119	144	173
2.0	58	69	83	100	122	147	177
2.2	59	70	85	102	124	150	181
2.4	60	72	86	105	127	153	184
2.6	61	73	88	107	129	156	188
2.8	62	74	89	109	132	159	191
3.0	63	76	91	111	134	162	195
¹ These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature and at the higher pH.

Table 1.5 CT values (CT99.9) for 99.9 percent inactivation of giardia lamblia cysts by free chlorine at 20.0°C¹
Free Residual (mg/L)	pH
	<6.0	6.5	7.0	7.5	8.0	8.5	<9.0
<0.4	36	44	52	62	74	89	105
0.6	38	45	54	64	77	92	109
0.8	39	46	55	66	79	95	113
1.0	39	47	56	67	81	98	117
1.2	40	48	57	69	83	100	120
1.4	41	49	58	70	85	103	123
1.6	42	50	59	72	87	105	126
1.8	43	51	61	74	89	108	129
2.0	44	52	62	75	91	110	132
2.2	44	53	63	77	93	113	135
2.4	45	54	65	78	95	115	138
2.6	46	55	66	80	97	117	141
2.8	47	56	67	81	99	119	143
3.0	47	57	68	83	101	122	146
¹ These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature and at the higher pH.

Table 1.6 CT values (CT99.9) for 99.9 percent inactivation of giardia lamblia cysts by free chlorine at 25°C¹ and higher
Free Residual (mg/L)	pH
	<6.0	6.5	7.0	7.5	8.0	8.5	<9.0
<0.4	24	29	35	42	50	59	70
0.6	25	30	36	43	51	61	73
0.8	26	31	37	44	53	63	75
1.0	26	31	37	45	54	65	78
1.2	27	32	38	46	55	67	80
1.4	27	33	39	47	57	69	82
1.6	28	33	40	48	58	70	84
1.8	29	34	41	49	60	72	86
2.0	29	35	41	50	61	74	88
2.2	30	35	42	51	62	75	90
2.4	30	36	43	52	63	77	92
2.6	31	37	44	53	65	78	94
2.8	31	37	45	54	66	80	96
3.0	32	38	46	55	67	81	97
¹ These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature and at the higher pH.

Table 2.1 CT values (CT99.9) for 99.9 percent inactivation of giardia lamblia cysts by chlorine dioxide and ozone¹
Free Residual (mg/L)	Temperature
	1°C	5°C	10°C	15°C	20°C	&>25°C
Chlorinedioxide	63	26	23	19	15	11
Ozone	2.0	1.9	1.4	0.95	0.72	0.46
¹ These CT values achieve greater than 99.99 percent inactivation of viruses. CT values between the indicated temperatures may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature for determining CT99.9 values between indicated temperatures.

Table 3.1 CT values (CT99.9) for 99.9 percent inactivation of giardia lamblia cysts by chloramines¹ Temperature
<1°C	5°C	10°C	15°C	20°C	&>25°C
2.0	1.9	1.4	0.95	0.72	0.46
¹ These values are for pH values of 6 to 9. These CT values may be assumed to achieve greater than 99.99 percent inactivation of viruses only if chlorine is added and mixed in the water prior to the addition of ammonia. If this condition is not met, the system must demonstrate, based on on-site studies or other information, as approved by the State, that the system is achieving at least 99.99 percent inactivation of viruses. CT values between the indicated temperatures may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature for determining CT99.9 values between indicated temperatures.

1.6.9Enhanced Treatment for Cryptosporidium

A. General Requirements

1. The requirements of § 1.6.9 of this Part are National Primary Drinking Water Regulations. The Regulations in § 1.6.9 of this Part establish or extend treatment technique requirements in lieu of maximum contaminant levels for Cryptosporidium. These requirements are in addition to requirements for filtration and disinfection in other sections of this Part.

2. Applicability. The requirements of § 1.6.9 of this Part apply to all PWS subject to § 1.6 of this Part, which are PWS supplied by a surface water source and PWS supplied by a groundwater source under the direct influence of surface water.

a. Wholesale PWS, as defined in § 1.2 of this Part, must comply with the requirements of § 1.6.9 of this Part, based on the population of the largest PWS in the combined distribution system.

b. The requirements of § 1.6.9 of this Part for filtered PWS apply to PWS required by National Primary Drinking Water Regulations to provide filtration treatment, whether or not the PWS is currently operating a filtration system.

c. The requirements of § 1.6.9 of this Part for unfiltered PWS apply only to unfiltered PWS that timely met and continue to meet the filtration avoidance criteria in § 1.6 of this Part, as applicable.

3. Requirements. PWS subject to § 1.6.9 of this Part, must comply with the following requirements:

a. PWS must conduct an initial and a second round of source water monitoring for each plant that treats a surface water or GWUDI source. This monitoring may include sampling for Cryptosporidium, E. coli, and turbidity as described in §§ 1.6.9(B) through 1.6.9(G) of this Part, to determine what level, if any, of additional Cryptosporidium treatment they must provide.

b. PWS that plan to make a significant change to their disinfection practice must develop disinfection profiles and calculate disinfection benchmarks, as described in §§ 1.6.9(I) through 1.6.9(J) of this Part.

c. Filtered PWS must determine their Cryptosporidium treatment bin classification as described in § 1.6.9(K) of this Part and provide additional treatment for Cryptosporidium, if required, as described in § 1.6.9(L) of this Part. All unfiltered PWS must provide treatment for Cryptosporidium as described in § 1.6.9(M) of this Part. Filtered and unfiltered PWS must implement Cryptosporidium treatment according to the schedule in § 1.6.9(N) of this Part.

d. PWS required to provide additional treatment for Cryptosporidium must implement microbial toolbox options that are designed and operated as described in §§ 1.6.9(O) through 1.6.9(T) of this Part.

e. PWS must comply with the applicable recordkeeping and reporting requirements described in §§ 1.6.9(U) through 1.6.9(V) of this Part.

f. PWS must address significant deficiencies identified in sanitary surveys performed as described in § 1.6.9(W) of this Part.

B. Source Water Monitoring

1. Initial Round of Source Water Monitoring. PWS must conduct the following monitoring on the schedule in § 1.6.9(B)(3) of this Part unless they meet the monitoring exemption criteria in § 1.6.9(B)(4) of this Part.

a. Filtered PWS serving at least 10,000 people must sample their source water for Cryptosporidium, E. coli, and turbidity at least monthly for twenty-four (24) months.

b. Unfiltered PWS serving at least 10,000 people must sample their source water for Cryptosporidium at least monthly for twenty-four (24) months.

c. Filtered PWS serving fewer than 10,000 people must sample their source water for E. coli at least once every two weeks for twelve (12) months.

(1) A filtered PWS serving fewer than 10,000 people may avoid E. coli monitoring if the PWS notifies the Director that it will monitor for Cryptosporidium as described in § 1.6.9(B)(1)(d) of this Part. The PWS must notify the Director no later than 3 months prior to the date the PWS is otherwise required to start E. coli monitoring under § 1.6.9(B)(3) of this Part.

d. Filtered PWS serving fewer than 10,000 people must sample their source water for Cryptosporidium at least twice per month for twelve (12) months or at least monthly for twenty-four (24) months if they meet one of the following, based on monitoring conducted under § 1.6.9(B)(1)(c) of this Part:

(1) For PWS using lake/reservoir sources, the annual mean E. coli concentration is greater than 10 E. coli/100 mL.

(2) For PWS using flowing stream sources, the annual mean E. coli concentration is greater than 50 E. coli/100 mL.

(3) The PWS does not conduct E. coli monitoring as described in § 1.6.9(B)(1)(c) of this Part.

(4) PWS using groundwater under the direct influence of surface water (GWUDI) must comply with the requirements of § 1.6.9(B)(1)(d) of this Part, based on the E. coli level that applies to the nearest surface water body. If no surface water body is nearby, the PWS must comply based on the requirements that apply to PWS using lake/reservoir sources.

e. For filtered PWS serving fewer than 10,000 people, the Director may approve monitoring for an indicator other than E. coli under § 1.6.9(B)(1)(c) of this Part. The Director also may approve an alternative to the E. coli concentration in §§ 1.6.9(B)(1)(d) ((1)), ((2)) or ((4)) of this Part, to trigger Cryptosporidium monitoring. This approval by the Director must be provided to the PWS in writing and must include the basis for the Director's determination that the alternative indicator and/or trigger level will provide a more accurate identification of whether a PWS will exceed the Bin 1 Cryptosporidium level in § 1.6.9(K) of this Part.

f. Unfiltered PWS serving fewer than 10,000 people must sample their source water for Cryptosporidium at least twice per month for twelve (12) months or at least monthly for twenty-four (24) months.

g. PWS may sample more frequently than required under this Section if the sampling frequency is evenly spaced throughout the monitoring period.

2. Second Round of Source Water Monitoring. PWS must conduct a second round of source water monitoring that meets the requirements for monitoring parameters, frequency, and duration described in § 1.6.9(B)(1) of this Part, unless they meet the monitoring exemption criteria in § 1.6.9(B)(4) of this Part. PWS must conduct this monitoring on the schedule in § 1.6.9(B)(3) of this Part.

3. Monitoring Schedule. PWS must begin the monitoring required in §§ 1.6.9(B)(1) and (2) of this Part, no later than the month beginning with the date listed in the table below:

SOURCE WATER MONITORING STARTING DATES TABLE
PWS that serve:	Must begin the first round of source water monitoring no later than the month beginning:	And must begin the second round of source water monitoring no later than the month beginning:
(1) At least 100,000 people	(i) October 1, 2006.	(ii) April 1, 2015
(2) From 50,000 to 99,999 people	(i) April 1, 2007	(ii) October 1, 2015
(3) From 10,000 to 49,999 people	(i) April 1, 2008	(ii) October 1, 2016
(4) Fewer than 10,000 and monitor for E. coli (applies only to filtered PWS)	(i) October 1, 2008	(ii) October 1, 2017
(5) Fewer than 10,000 and monitor for Cryptosporidium (applies to filtered PWS that meet the conditions of § 1.6.9(B)(1)(d) of this Part and unfiltered PWS)	(i) April 1, 2010	(ii) April 1, 2019

4. Monitoring Avoidance

a. Filtered PWS are not required to conduct source water monitoring under § 1.6.9 of this Part if the PWS will provide a total of at least 5.5-log of treatment for Cryptosporidium, equivalent to meeting the treatment requirements of Bin 4 in § 1.6.9(L) of this Part.

b. Unfiltered PWS are not required to conduct source water monitoring under § 1.6.9 of this Part, if the PWS will provide a total of at least 3-log Cryptosporidium inactivation, equivalent to meeting the treatment requirements for unfiltered PWSs with a mean Cryptosporidium concentration of greater than 0.01 oocysts/L in § 1.6.9(M) of this Part.

c. If a PWS chooses to provide the level of treatment in § 1.6.9(B)(4)(a) or (b) of this Part, as applicable, rather than start source water monitoring, the PWS must notify the Director in writing no later than the date the PWS is otherwise required to submit a sampling schedule for monitoring under § 1.6.9(C) of this Part. Alternatively, a PWS may choose to stop sampling at any point after it has initiated monitoring if it notifies the Director in writing that it will provide this level of treatment. PWS must install and operate technologies to provide this level of treatment by the applicable treatment compliance date in § 1.6.9(N) of this Part.

5. Plants Operating Only Part of The Year. PWS with treatment plants that must comply with § 1.6 of this Part and that operate for only part of the year must conduct source water monitoring in accordance with § 1.6.9 of this Part, but with the following modifications:

a. PWS must sample their source water only during the months that the plant operates unless the Director specifies another monitoring period based on plant operating practices.

b. PWS with plants that operate less than six (6) months per year and that monitor for Cryptosporidium must collect at least six (6) Cryptosporidium samples per year during each of two (2) years of monitoring. Samples must be evenly spaced throughout the period the plant operates.

6. New Sources. A PWS that begins using a new source of surface water or GWUDI after the PWS is required to begin monitoring under § 1.6.9(B)(3) of this Part, must monitor the new source on a schedule the Director approves. Source water monitoring must meet the requirements of this § 1.6.9 of this Part. The PWS must also meet the bin classification and Cryptosporidium treatment requirements of §§ 1.6.9(K) and (L) or (M) of this Part, as applicable, for the new source on a schedule the Director approves.

a. The requirements of § 1.6.9(B)(6) of this Part, apply to PWS that must comply with § 1.6 and that begin operation after the monitoring start date applicable to the PWS's size under § 1.6.9(B)(3) of this Part.

b. The PWS must begin a second round of source water monitoring no later than six (6) years following initial bin classification under § 1.6.9(K) of this Part, or determination of the mean Cryptosporidium level under § 1.6.9(M) of this Part, as applicable.

7. Failure to collect any source water sample required under § 1.6.9(B) of this Part, in accordance with the sampling schedule, sampling location, analytical method, approved laboratory, and reporting requirements of §§ 1.6.9(C) through (G) of this Part, is a monitoring violation.

8. Grandfathering Monitoring Data. PWS may use (grandfather) monitoring data collected prior to the applicable monitoring start date in § 1.6.9(B)(3) of this Part, to meet the initial source water monitoring requirements in § 1.6.9(B)(1) of this Part. Grandfathered data may substitute for an equivalent number of months at the end of the monitoring period. All data submitted under § 1.6.9(B)(8) of this Part, must meet the requirements in § 1.6.9(H) of this Part.

C. Sampling Schedules

1. PWS required to conduct source water monitoring under § 1.6.9(B) of this Part, must submit a sampling schedule that specifies the calendar dates when the PWS will collect each required sample.

a. PWS must submit sampling schedules no later than three (3) months prior to the applicable date listed in § 1.6.9(B)(3) of this Part, for each round of required monitoring.

b. PWS serving at least 10,000 people must submit their sampling schedule for the initial round of source water monitoring under § 1.6.9(B)(1) of this Part, to EPA electronically.

(1) If a PWS is unable to submit the sampling schedule electronically, the PWS may use an alternative approach for submitting the sampling schedule that EPA approves.

c. PWS serving fewer than 10,000 people must submit their sampling schedules for the initial round of source water monitoring § 1.6.9(B)(1) of this Part, to the Director.

d. PWS must submit sampling schedules for the second round of source water monitoring under § 1.6.9(B)(2) of this Part to the Director.

e. If EPA or the Director does not respond to a PWS regarding its sampling schedule, the PWS must sample at the reported schedule.

2. PWS must collect samples within two (2) days before or two (2) days after the dates indicated in their sampling schedule (i.e., within a five-day period around the schedule date) unless one of the conditions of §§ 1.6.9(C)(2)(a) or (b) of this Part applies.

a. If an extreme condition or situation exists that may pose danger to the sample collector, or that cannot be avoided and causes the PWS to be unable to sample in the scheduled five-day period, the PWS must sample as close to the scheduled date as is feasible unless the Director approves an alternative sampling date. The PWS must submit an explanation for the delayed sampling date to the Director concurrent with the shipment of the sample to the laboratory.

b. If a PWS is unable to report a valid analytical result for a scheduled sampling date due to equipment failure, loss of or damage to the sample, failure to comply with the analytical method requirements, including the quality control requirements in § 1.6.9(E) of this Part, or the failure of an approved laboratory to analyze the sample, then the PWS must collect a replacement sample.

(1) The PWS must collect the replacement sample not later than twenty-one (21) days after receiving information that an analytical result cannot be reported for the scheduled date unless the PWS demonstrates that collecting a replacement sample within this time frame is not feasible or the Director approves an alternative resampling date. The PWS must submit an explanation for the delayed sampling date to the Director concurrent with the shipment of the sample to the laboratory.

3. PWSs that fail to meet the criteria of § 1.6.9(C)(2) of this Part, for any source water sample required under § 1.6.9(B) of this Part, must revise their sampling schedules to add dates for collecting all missed samples. PWSs must submit the revised schedule to the Director for approval prior to when the PWS begins collecting the missed samples.

D. Sampling Locations

1. PWSs required to conduct source water monitoring under § 1.6.9(B) of this Part, must collect samples for each plant that treats a surface water or GWUDI source. Where multiple plants draw water from the same influent, such as the same pipe or intake, the Director may approve one set of monitoring results to be used to satisfy the requirements of § 1.6.9(B) of this Part, for all plants.

2. PWSs must collect source water samples prior to chemical treatment, such as coagulants, oxidants, and disinfectants, unless the PWS meets the condition of § 1.6.9(D)(2)(a) of this Part.

a. The Director may approve a PWS to collect a source water sample after chemical treatment. To grant this approval, the Director must determine that collecting a sample prior to chemical treatment is not feasible for the PWS and that the chemical treatment is unlikely to have a significant adverse effect on the analysis of the sample.

3. PWSs that recycle filter backwash water must collect source water samples prior to the point of filter backwash water addition.

4. Bank Filtration

a. PWSs that receive Cryptosporidium treatment credit for bank filtration under § 1.6.4(C) of this Part, must collect source water samples in the surface water prior to bank filtration.

b. PWSs that use bank filtration as pretreatment to a filtration plant must collect source water samples from the well (i.e., after bank filtration). Use of bank filtration during monitoring must be consistent with routine operational practice. PWSs collecting samples after a bank filtration process may not receive treatment credit for the bank filtration under § 1.6.9(Q)(3) of this Part.

5. Multiple Sources. PWSs with plants that use multiple water sources, including multiple surface water sources and blended surface water and groundwater sources, must collect samples as specified in §§ 1.6.9(D)(5)(a) or (b) of this Part. The use of multiple sources during monitoring must be consistent with routine operational practice.

a. If a sampling tap is available where the sources are combined prior to treatment, PWSs must collect samples from the tap.

b. If a sampling tap where the sources are combined prior to treatment is not available, PWSs must collect samples at each source near the intake on the same day and must follow either §§ 1.6.9(D)(5)(b) ((1)) or ((2)) of this Part, for sample analysis.

(1) PWSs may composite samples from each source into one sample prior to analysis. The volume of sample from each source must be weighted according to the proportion of the source in the total plant flow at the time the sample is collected.

(2) PWSs may analyze samples from each source separately and calculate a weighted average of the analysis results for each sampling date. The weighted average must be calculated by multiplying the analysis result for each source by the fraction the source contributed to total plant flow at the time the sample was collected and then summing these values.

6. Additional Requirements. PWSs must submit a description of their sampling location(s) to the Director at the same time as the sampling schedule required under § 1.6.9(C) of this Part. This description must address the position of the sampling location in relation to the PWS's water source(s) and treatment processes, including pretreatment, points of chemical treatment, and filter backwash recycle. If the Director does not respond to a PWS regarding sampling location(s), the PWS must sample at the reported location(s).

E. Analytical Methods

1. Cryptosporidium. PWSs must analyze for Cryptosporidium using Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA, 2005, United States Environmental Protection Agency, EPA-815-R-05-002 or Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 2005, United States Environmental Protection Agency, EPA-815-R-05-001, which are incorporated by reference.

a. PWSs must analyze at least a 10 L sample or a packed pellet volume of at least 2 mL as generated by the methods listed in § 1.6.9(E)(1) of this Part. PWSs unable to process a 10 L sample must analyze as much sample volume as can be filtered by two filters approved by EPA for the methods listed in § 1.6.9(E)(1) of this Part, up to a packed pellet volume of at least 2 mL.

b. Matrix spike (MS) samples, as required by the methods in § 1.6.9(E)(1) of this Part, must be spiked and filtered by a laboratory approved for Cryptosporidium analysis under § 1.6.9(F) of this Part.

(1) If the volume of the MS sample is greater than 10 L, the PWS may filter all but 10 L of the MS sample in the field, and ship the filtered sample and the remaining 10 L of source water to the laboratory. In this case, the laboratory must spike the remaining 10 L of water and filter it through the filter used to collect the balance of the sample in the field.

c. Flow cytometer-counted spiking suspensions must be used for MS samples and ongoing precision and recovery (OPR) samples.

2. E. coli. PWSs must use methods for enumeration of E. coli in source water approved in § 1.21 of this Part.

a. The time from sample collection to initiation of analysis may not exceed thirty (30) hours unless the PWS meets the condition of § 1.6.9(E)(2)(b) of this Part.

b. The Director may approve on a case-by-case basis the holding of an E. coli sample for up to forty-eight (48) hours between sample collection and initiation of analysis if the Director determines that analyzing an E. coli sample within thirty (30) hours is not feasible. E. coli samples held between 30 to 48 hours must be analyzed by the Colilert reagent version of Standard Method 9223B as listed in § 1.21 of this Part.

c. PWSs must maintain samples between 0 degrees C and 10 degrees C during storage and transit to the laboratory.

3. Turbidity. PWSs must use methods for turbidity measurement approved in § 1.21 of this Part.

F. Approved Laboratories

1. Cryptosporidium. PWSs must have Cryptosporidium samples analyzed by a laboratory that is approved under EPA's Laboratory Quality Assurance Evaluation Program for Analysis of Cryptosporidium in Water or a laboratory that has been certified for Cryptosporidium analysis by an equivalent laboratory certification program approved by the Director.

2. E. coli. Any laboratory certified by the EPA, the National Environmental Laboratory Accreditation Conference, or the Director for total coliform or fecal coliform analysis under § 1.12 of this Part, is approved for E. coli analysis under § 1.6.9 of this Part, when the laboratory uses the same technique for E. coli that the laboratory uses for § 1.12 of this Part.

3. Turbidity. Measurements of turbidity must be made by a party approved by the Director.

G. Reporting Source Water Monitoring Results

1. PWSs must report results from the source water monitoring required under § 1.6.9(B) of this Part, no later than ten (10) days after the end of the first month following the month when the sample is collected.

2. All PWSs serving at least 10,000 people must report the results from the initial source water monitoring required under § 1.6.9(B)(1) of this Part, to EPA electronically.

a. If a PWS is unable to report monitoring results electronically, the PWS may use an alternative approach for reporting monitoring results that EPA approves.

3. PWSs serving fewer than 10,000 people must report results from the initial source water monitoring required under § 1.6.9(B)(1) of this Part, to the Director.

4. All PWSs must report results from the second round of source water monitoring required under § 1.6.9(B)(2) of this Part to the Director.

5. PWSs must report the applicable information in §§ 1.6.9(G)(5)(a) and (b) of this Part, for the source water monitoring required under § 1.6.9(B) of this Part.

a. PWSs must report the following data elements for each Cryptosporidium analysis:

(1) PWS ID.

(2) Facility ID.

(3) Sample collection date.

(4) Sample type (field or matrix spike).

(5) Sample volume filtered (L), to nearest ¼ L.

(6) Was 100% of filtered volume examined.

(7) Number of oocysts counted.

(AA) For matrix spike samples, PWSs must also report the sample volume spiked and estimated number of oocysts spiked. These data are not required for field samples.

(BB) For samples in which less than 10 L is filtered or less than 100% of the sample volume is examined, PWSs must also report the number of filters used and the packed pellet volume.

(CC) For samples in which less than 100% of sample volume is examined, PWSs must also report the volume of resuspended concentrate and volume of this resuspension processed through immunomagnetic separation.

b. PWSs must report the following data elements for each E. coli analysis:

(1) PWS ID.

(2) Facility ID.

(3) Sample collection date.

(4) Analytical method number.

(5) Method type.

(6) Source type (flowing stream, lake/reservoir, GWUDI).

(7) E. coli/100 mL.

(8) Turbidity. PWSs serving fewer than 10,000 people that are not required to monitor for turbidity under § 1.6.9(B) of this Part, are not required to report turbidity with their E. coli results.

H. Grandfathering Previously Collected Data

1. PWSs may comply with the initial source water monitoring requirements of § 1.6.9(B)(1) of this Part, by grandfathering sample results collected before the PWS is required to begin monitoring (i.e., previously collected data). To be grandfathered, the sample results and analysis must meet the criteria in this Section and the Director must approve.

a. A filtered PWS may grandfather Cryptosporidium samples to meet the requirements of § 1.6.9(B)(1) of this Part, when the PWS does not have corresponding E. coli and turbidity samples.

b. A PWS that grandfathers Cryptosporidium samples without E. coli and turbidity samples is not required to collect E. coli and turbidity samples when the PWS completes the requirements for Cryptosporidium monitoring under § 1.6.9(B)(1) of this Part.

2. E. coli Sample Analysis. The analysis of E. coli samples must meet the analytical method and approved laboratory requirements of §§ 1.6.9(E) through (F) of this Part.

3. Cryptosporidium Sample Analysis. The analysis of Cryptosporidium samples must meet the criteria in this paragraph.

a. Laboratories analyzed Cryptosporidium samples using one of the analytical methods in §§ 1.6.9(H)(3)(a) ((1)) through ((6)) of this Part.

(1) Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA, 2005, United States Environmental Protection Agency, EPA-815-R-05-002.

(2) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 2005, United States Environmental Protection Agency, EPA-815-R-05-001.

(3) Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA, 2001, United States Environmental Protection Agency, EPA-821-R-01-025.

(4) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 2001, United States Environmental Protection Agency, EPA-821--R-01-026.

(5) Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA, 1999, United States Environmental Protection Agency, EPA-821-R-99-006.

(6) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 1999, United States Environmental Protection Agency, EPA-821-R-99-001.

b. For each Cryptosporidium sample, the laboratory analyzed at least 10 L of sample or at least 2 mL of packed pellet or as much volume as could be filtered by 2 filters that EPA approved for the methods listed in § 1.6.9(H)(3)(a) of this Part.

4. Sampling Location. The sampling location must meet the conditions in § 1.6.9(D) of this Part.

5. Sampling Frequency. Cryptosporidium samples were collected no less frequently than each calendar month on a regular schedule, beginning no earlier than January 1999. Sample collection intervals may vary for the conditions specified in §§ 1.6.9(C)(2)(a) and (b) of this Part, if the PWS provides documentation of the condition when reporting monitoring results.

a. The Director may approve grandfathering of previously collected data where there are time gaps in the sampling frequency if the PWS conducts additional monitoring the Director specifies to ensure that the data used to comply with the initial source water monitoring requirements of § 1.6.9(B)(1) of this Part, are seasonally representative and unbiased.

b. PWSs may grandfather previously collected data where the sampling frequency within each month varied. If the Cryptosporidium sampling frequency varied, PWSs must follow the monthly averaging procedure in §§ 1.6.9(K)(2)(e) or 1.6.9(M)(1)(c) of this Part, as applicable, when calculating the bin classification for filtered PWSs or the mean Cryptosporidium concentration for unfiltered PWSs.

6. Reporting Monitoring Results for Grandfathering. PWSs that request to grand-father previously collected monitoring results must report the following information by the applicable dates listed in this paragraph. PWSs serving at least 10,000 people must report this information to EPA unless the Director approves reporting to the Director rather than EPA. PWSs serving fewer than 10,000 people must report this information to the Director.

a. PWSs must report that they intend to submit previously collected monitoring results for grandfathering. This report must specify the number of previously collected results the PWS will submit, the dates of the first and last sample, and whether a PWS will conduct additional source water monitoring to meet the requirements of § 1.6.9(B)(1) of this Part. PWSs must report this information no later than the date the sampling schedule under § 1.6.9(C) of this Part, is required.

b. PWSs must report previously collected monitoring results for grandfathering, along with the associated documentation listed in §§ 1.6.9(H)(6)(b) ((1)) through ((4)) of this Part, no later than two months after the applicable date listed in § 1.6.9(B)(3) of this Part.

(1) For each sample result, PWSs must report the applicable data elements in § 1.6.9(G) of this Part.

(2) PWSs must certify that the reported monitoring results include all results the PWS generated during the time period beginning with the first reported result and ending with the final reported result. This applies to samples that were collected from the sampling location specified for source water monitoring under § 1.6.9 of this Part, not spiked, and analyzed using the laboratory's routine process for the analytical methods listed in this Section.

(3) PWSs must certify that the samples were representative of a plant's source water(s) and the source water(s) have not changed. PWSs must report a description of the sampling location(s), which must address the position of the sampling location in relation to the PWS's water source(s) and treatment processes, including points of chemical addition and filter backwash recycle.

(4) For Cryptosporidium samples, the laboratory or laboratories that analyzed the samples must provide a letter certifying that the quality control criteria specified in the methods listed in § 1.6.9(H)(3)(a) of this Part, were met for each sample batch associated with the reported results. Alternatively, the laboratory may provide bench sheets and sample examination report forms for each field, matrix spike, IPR, OPR, and method blank sample associated with the reported results.

7. If the Director determines that a previously collected data set submitted for grandfathering was generated during source water conditions that were not normal for the PWS, such as a drought, the Director may disapprove the data. Alternatively, the Director may approve the previously collected data if the PWS reports additional source water monitoring data, as determined by the Director, to ensure that the data set used under §§ 1.6.9(K) or 1.6.9(M) of this Part, represents average source water conditions for the PWS.

8. If a PWS submits previously collected data that fully meet the number of samples required for initial source water monitoring under § 1.6.9(B)(1) of this Part, and some of the data are rejected due to not meeting the requirements of this Section, PWSs must conduct additional monitoring to replace rejected data on a schedule the Director approves. PWSs are not required to begin this additional monitoring until two months after notification that data have been rejected and additional monitoring is necessary.

I. Requirements When Making a Significant Change in Disinfection Practice

1. Following the completion of initial source water monitoring under § 1.6.9(B)(1) of this Part, a PWS that plans to make a significant change to its disinfection practice, as defined in § 1.6.9(I)(2) of this Part, must develop disinfection profiles and calculate disinfection benchmarks for Giardia lamblia and viruses as described in § 1.6.9(J) of this Part. Prior to changing the disinfection practice, the PWS must notify the Director and must include in this notice the information in §§ 1.6.9(I)(1)(a) through (c) of this Part.

a. A completed disinfection profile and disinfection benchmark for Giardia lamblia and viruses as described in § 1.6.9(J) of this Part.

b. A description of the proposed change in disinfection practice.

c. An analysis of how the proposed change will affect the current level of disinfection.

2. Significant changes to disinfection practice are defined as follows:

a. Changes to the point of disinfection;

b. Changes to the disinfectant(s) used in the treatment plant;

c. Changes to the disinfection process; or

d. Any other modification identified by the Director as a significant change to disinfection practice.

J. Developing the Disinfection Profile and Benchmark

1. PWSs required to develop disinfection profiles under § 1.6.9(I) of this Part, must follow the requirements of this Section. PWSs must monitor at least weekly for a period of 12 consecutive months to determine the total log inactivation for Giardia lamblia and viruses. If PWSs monitor more frequently, the monitoring frequency must be evenly spaced. PWSs that operate for fewer than 12 months per year must monitor weekly during the period of operation. PWSs must determine log inactivation for Giardia lamblia through the entire plant, based on CT99.9 values in Tables 1.1 through 1.6, 2.1 and 3.1 of § 1.6.8 of this Part, as applicable. PWSs must determine log inactivation for viruses through the entire treatment plant based on a protocol approved by the Director.

2. PWSs with a single point of disinfectant application prior to the entrance to the distribution PWS must conduct the monitoring in §§ 1.6.9(J)(2)(a) through (d) of this Part. PWSs with more than one point of disinfectant application must conduct the monitoring in §§ 1.6.9(J)(2)(a) through (d) of this Part, for each disinfection segment. PWSs must monitor the parameters necessary to determine the total inactivation ratio, using analytical methods in § 1.21 of this Part.

a. For PWSs using a disinfectant other than UV, the temperature of the disinfected water must be measured at each residual disinfectant concentration sampling point during peak hourly flow or at an alternative location approved by the Director.

b. For PWSs using chlorine, the pH of the disinfected water must be measured at each chlorine residual disinfectant concentration sampling point during peak hourly flow or at an alternative location approved by the Director.

c. The disinfectant contact time(s) (t) must be determined during peak hourly flow.

d. The residual disinfectant concentration(s) (C) of the water before or at the first customer and prior to each additional point of disinfectant application must be measured during peak hourly flow.

3. In lieu of conducting new monitoring under § 1.6.9(J)(2) of this Part, PWSs may elect to meet the requirements of §§ 1.6.9(J)(3)(a) or (b) of this Part.

a. PWSs that have at least one year of existing data that are substantially equivalent to data collected under the provisions of § 1.6.9(J)(2) of this Part, may use these data to develop disinfection profiles as specified in this Section if the PWS has neither made a significant change to its treatment practice nor changed sources since the data were collected. PWSs may develop disinfection profiles using up to three years of existing data.

b. PWSs may use disinfection profile(s) developed under § 1.6.3(G) or §§ 1.6.6(A)(3) and (4) of this Part, in lieu of developing a new profile if the PWS has neither made a significant change to its treatment practice nor changed sources since the profile was developed. PWSs that have not developed a virus profile under § 1.6.3(G) or §§ 1.6.6(A)(3) and (4) of this Part, must develop a virus profile using the same monitoring data on which the Giardia lamblia profile is based.

4. PWSs must calculate the total inactivation ratio for Giardia lamblia as specified in §§ 1.6.9(J)(4)(a) through (c) of this Part.

a. PWSs using only one point of disinfectant application may determine the total inactivation ratio for the disinfection segment based on either of the methods in §§ 1.6.9(J)(4)(a) ((1)) or ((2)) of this Part.

(1) Determine one inactivation ratio (CTcalc/CT99.9) before or at the first customer during peak hourly flow.

(2) Determine successive CTcalc/CT99.9 values, representing sequential inactivation ratios, between the point of disinfectant application and a point before or at the first customer during peak hourly flow. The PWS must calculate the total inactivation ratio by determining (CTcalc/CT99.9) for each sequence and then adding the (CTcalc/CT99.9) values together to determine ([SIGMA] (CTcalc/CT99.9)).

b. PWSs using more than one point of disinfectant application before the first customer must determine the CT value of each disinfection segment immediately prior to the next point of disinfectant application, or for the final segment, before or at the first customer, during peak hourly flow. The (CTcalc/CT99.9) value of each segment and ([SIGMA] (CTcalc/CT99.9)) must be calculated using the method in § 1.6.9(J)(4)(a) ((2)) of this Part.

c. The PWS must determine the total logs of inactivation by multiplying the value calculated in §§ 1.6.9(J)(4)(a) or (b) of this Part by 3.0.

d. PWSs must calculate the log of inactivation for viruses using a protocol approved by the Director.

5. PWSs must use the procedures specified in §§ 1.6.9(J)(5)(a) and (b) of this Part to calculate a disinfection benchmark.

a. For each year of profiling data collected and calculated under §§ 1.6.9(J)(1) through (4) of this Part, PWSs must determine the lowest mean monthly level of both Giardia lamblia and virus inactivation. PWSs must determine the mean Giardia lamblia and virus inactivation for each calendar month for each year of profiling data by dividing the sum of daily or weekly Giardia lamblia and virus log inactivation by the number of values calculated for that month.

b. The disinfection benchmark is the lowest monthly mean value (for PWSs with one year of profiling data) or the mean of the lowest monthly mean values (for PWSs with more than one year of profiling data) of Giardia lamblia and virus log inactivation in each year of profiling data.

K. Bin Classification for Filtered PWSs

1. Following completion of the initial round of source water monitoring required under § 1.6.9(B)(1) of this Part, filtered PWSs must calculate an initial Cryptosporidium bin concentration for each plant for which monitoring was required. Calculation of the bin concentration must use the Cryptosporidium results reported under § 1.6.9(B)(1) of this Part and must follow the procedures in §§ 1.6.9(K)(2)(a) through (e) of this Part.

2. Procedures

a. For PWSs that collect a total of at least forty-eight (48) samples, the bin concentration is equal to the arithmetic mean of all sample concentrations.

b. For PWSs that collect a total of at least twenty-four (24) samples, but not more than forty-seven (47) samples, the bin concentration is equal to the highest arithmetic mean of all sample concentrations in any twelve (12) consecutive months during which Cryptosporidium samples were collected.

c. For PWSs that serve fewer than 10,000 people and monitor for Cryptosporidium for only one year (i.e., collect 24 samples in 12 months), the bin concentration is equal to the arithmetic mean of all sample concentrations.

d. For PWSs with plants operating only part of the year that monitor fewer than twelve (12) months per year under § 1.6.9(B)(5) of this Part, the bin concentration is equal to the highest arithmetic mean of all sample concentrations during any year of Cryptosporidium monitoring.

e. If the monthly Cryptosporidium sampling frequency varies, PWSs must first calculate a monthly average for each month of monitoring. PWSs must then use these monthly average concentrations, rather than individual sample concentrations, in the applicable calculation for bin classification in §§ 1.6.9(K)(2)(a) through (d) of this Part.

3. Filtered PWSs must determine their initial bin classification from the following table and using the Cryptosporidium bin concentration calculated under §§ 1.6.9(K)(1) and (2) of this Part:

BIN CLASSIFICATION TABLE FOR FILTERED PWS
For PWS that are:	With a Cryptosporidium bin concentration of (Based on calculations in § 1.6.9(K)(1) or (2) of this Part, as applicable)	The bin classification is
Required to monitor for Cryptosporidium under § 1.6.9(B) of this Part	Cryptosporidium <0.075 oocyst/L	Bin 1
	0.075 oocysts/L [LESS THAN OR EQUAL TO] Cryptosporidium <1.0 oocysts/L	Bin 2
	1.0 oocysts/L [LESS THAN OR EQUAL TO] Cryptosporidium <3.0 oocysts/L	Bin 3
	Cryptosporidium [GREATER THAN OR EQUAL TO] 3.0 oocysts/L	Bin 4
Serving fewer than 10,000 people and NOT required to monitor for Cryptosporidium under § 1.6.9(B)(1)(d) of this Part.	NA	Bin 5

4. Following completion of the second round of source water monitoring required under § 1.6.9(B)(2) of this Part, filtered PWSs must recalculate their Cryptosporidium bin concentration using the Cryptosporidium results reported under § 1.6.9(B)(2) of this Part and following the procedures in §§ 1.6.9(K)(2)(a) through (d) of this Part. PWSs must then redetermine their bin classification using this bin concentration and the table in § 1.6.9(K)(3) of this Part.

5. Filtered PWSs must report their initial bin classification under § 1.6.9(K)(3) of this Part, to the Director for approval no later than six (6) months after the PWS is required to complete initial source water monitoring based on the schedule in § 1.6.9(B)(3) of this Part.

a. PWSs must report their bin classification under § 1.6.9(K)(4) of this Part, to the Director for approval no later than 6 months after the PWS is required to complete the second round of source water monitoring based on the schedule in § 1.6.9(B)(3) of this Part.

b. The bin classification report to the Director must include a summary of source water monitoring data and the calculation procedure used to determine bin classification.

6. Failure to comply with the conditions of § 1.6.9(K)(5) of this Part is a violation of the treatment technique requirement.

L. Filtered PWS Additional Cryptosporidium Treatment Requirements

1. Filtered PWSs must provide the level of additional treatment for Cryptosporidium specified in this paragraph based on their bin classification as determined under § 1.6.9(K) of this Part and according to the schedule in § 1.6.9(N) of this Part.

2. Filtered PWSs must use one or more of the treatment and management options listed in § 1.6.9(O) of this Part, termed the microbial toolbox, to comply with the additional Cryptosporidium treatment required in § 1.6.9(L)(1) of this Part.

If the PWS bin classification is	And the PWS uses the following filtration treatment in full compliance with § 1.5 of this Part (as applicable), then the additional Cryptosporidium treatment requirements are
(A)	Conventional filtration treatment (including softening)	Direct filtration	Slow sand or diatomaceous earth filtration	Alternative technologies
Bin 1	No additional treatment	No additional treatment	No additional treatment	No additional treatment
Bin 2	1-log treatment	1.5-log treatment	1-log treatment	As determined by the Director such that the total Cryptosporidium removal and inactivation is at least 4.0-log.
Bin 3	2-log treatment	2.5-log treatment	2-log treatment	As determined by the Director such that the total Cryptosporidium removal and inactivation is at least 5.0-log.
Bin 4	2.5-log treatment	3-log treatment	2.5-log treatment	As determined by the Director such that the total Cryptosporidium removal and inactivation is at least 5.5-log.

b. PWSs classified in Bin 3 and Bin 4 must achieve at least 1-log of the additional Cryptosporidium treatment required under § 1.6.9(L)(1) of this Part, using either one or a combination of the following: bag filters, bank filtration, cartridge filters, chlorine dioxide, membranes, ozone, or UV, as described in §§ 1.6.9(P) through (T) of this Part.

3. Failure by a PWS in any month to achieve treatment credit by meeting criteria in §§ 1.6.9(P) through (T) of this Part, for microbial toolbox options that is at least equal to the level of treatment required in § 1.6.9(L)(1) of this Part, is a violation of the treatment technique requirement.

4. If the Director determines during a sanitary survey or an equivalent source water assessment that after a PWS completed the monitoring conducted under §§ 1.6.9(B)(1) or 1.6.9(B)(2) of this Part, significant changes occurred in the PWS's watershed that could lead to increased contamination of the source water by Cryptosporidium, the PWS must take actions specified by the Director to address the contamination. These actions may include additional source water monitoring and/or implementing microbial toolbox options listed in § 1.6.9(O) of this Part.

M. Unfiltered PWS Cryptosporidium Treatment Requirements

1. Determination of Mean Cryptosporidium Level

a. Following completion of the initial source water monitoring required under § 1.6.9(B)(1) of this Part, unfiltered PWSs must calculate the arithmetic mean of all Cryptosporidium sample concentrations reported under § 1.6.9(B)(1) of this Part. PWSs must report this value to the Director for approval no later than six (6) months after the month the PWS is required to complete initial source water monitoring based on the schedule in § 1.6.9(B)(3) of this Part.

b. Following completion of the second round of source water monitoring required under § 1.6.9(B)(2) of this Part, unfiltered PWSs must calculate the arithmetic mean of all Cryptosporidium sample concentrations reported under § 1.6.9(B)(2) of this Part. PWSs must report this value to the Director for approval no later than six (6) months after the month the PWS is required to complete the second round of source water monitoring based on the schedule in § 1.6.9(B)(3) of this Part.

c. If the monthly Cryptosporidium sampling frequency varies, PWSs must first calculate a monthly average for each month of monitoring. PWSs must then use these monthly average concentrations, rather than individual sample concentrations, in the calculation of the mean Cryptosporidium level in §§ 1.6.9(M)(1)(a) or (b) of this Part.

d. The report to the Director of the mean Cryptosporidium levels calculated under §§ 1.6.9(M)(1)(a) and (b) of this Part must include a summary of the source water monitoring data used for the calculation.

e. Failure to comply with the conditions of § 1.6.9(M)(1) of this Part is a violation of the treatment technique requirement.

2. Cryptosporidium Inactivation Requirements. Unfiltered PWSs must provide the level of inactivation for Cryptosporidium specified in this paragraph, based on their mean Cryptosporidium levels as determined under § 1.6.9(M)(1) of this Part and according to the schedule in § 1.6.9(N) of this Part.

a. Unfiltered PWSs with a mean Cryptosporidium level of 0.01 oocysts/L or less must provide at least 2-log Cryptosporidium inactivation.

b. Unfiltered PWSs with a mean Cryptosporidium level of greater than 0.01 oocysts/L must provide at least 3-log Cryptosporidium inactivation.

3. Inactivation Treatment Technology Requirements. Unfiltered PWSs must use chlorine dioxide, ozone, or UV as described in § 1.6.9(T) of this Part, to meet the Cryptosporidium inactivation requirements of this Section.

a. PWSs that use chlorine dioxide or ozone and fail to achieve the Cryptosporidium inactivation required in § 1.6.9(M)(2) of this Part, on more than one day in the calendar month are in violation of the treatment technique requirement.

b. PWSs that use UV light and fail to achieve the Cryptosporidium inactivation required in § 1.6.9(M)(2) of this Part by meeting the criteria in § 1.6.9(T)(4)(c) ((2)) of this Part, are in violation of the treatment technique requirement.

4. Use of Two Disinfectants. Unfiltered PWSs must meet the combined Cryptosporidium inactivation requirements of this Section and Giardia lamblia and virus inactivation requirements of § 1.6.3(E) of this Part, using a minimum of two disinfectants, and each of two disinfectants must separately achieve the total inactivation required for either Cryptosporidium, Giardia lamblia, or viruses.

N. Schedule for Compliance with Cryptosporidium Treatment Requirements

1. Following initial bin classification under § 1.6.9(K)(3) of this Part, filtered PWSs must provide the level of treatment for Cryptosporidium required under § 1.6.9(L) of this Part, according to the schedule in § 1.6.9(N)(3) of this Part.

2. Following initial determination of the mean Cryptosporidium level under § 1.6.9(M)(1)(a) of this Part, unfiltered PWSs must provide the level of treatment for Cryptosporidium required under § 1.6.9(M) of this Part according to the schedule in § 1.6.9(N)(3) of this Part.

3. Cryptosporidium treatment compliance dates

CRYPTOSPORIDIUM TREATMENT COMPLIANCE DATES TABLE
PWS that serve:	Must comply with Cryptosporidium treatment requirements no later than (the Director may allow up to an additional two years for complying with the treatment requirement for systems making capital improvements):
a. At least 100,000 people	April 1, 2012
b. From 50,000 to 99,999 people	October 1, 2012
c. From 10,000 to 49,999 people	October 1, 2013
d. Fewer than 10,000 people	October 1, 2014

4. If the bin classification for a filtered PWS changes following the second round of source water monitoring, as determined under § 1.6.9(K)(4) of this Part, the PWS must provide the level of treatment for Cryptosporidium required under § 1.6.9(L) of this Part, on a schedule the Director approves.

5. If the mean Cryptosporidium level for an unfiltered PWS changes following the second round of monitoring, as determined under § 1.6.9(M)(1)(b) of this Part, and if the PWS must provide a different level of Cryptosporidium treatment under § 1.6.9(M) of this Part, due to this change, the PWS must meet this treatment requirement on a schedule the Director approves.

O. Microbial Toolbox Options for Meeting Cryptosporidium Treatment Requirements

1. PWSs receive the treatment credits listed in the table in § 1.6.9(O)(2) of this Part by meeting the conditions for microbial toolbox options described in §§ 1.6.9(P) through 1.6.9(T) of this Part.

a. PWSs apply these treatment credits to meet the treatment requirements in § 1.6.9(L) or 1.6.9(M) of this Part, as applicable.

b. Unfiltered PWSs are eligible for treatment credits for the microbial toolbox options described in § 1.6.9(T) of this Part, only.

2. The following table summarizes options in the microbial toolbox:

MICROBIAL TOOLBOX SUMMARY TABLE: OPTIONS, TREATMENT CREDITS AND CRITERIA
Toolbox Option	Cryptosporidium treatment credit with design and implementation criteria
Source Protection and Management Toolbox Options
(1) Watershed control program	0.5-log credit for Director-approved program comprising required elements, annual program status report to Director, and regular watershed survey. Unfiltered PWSs are not eligible for credit. Specific criteria are in § 1.6.9(P)(1) of this Part.
(2) Alternative source/intake management	No prescribed credit. PWSs may conduct simultaneous monitoring for treatment bin classification at alternative intake locations or under alternative intake management strategies. Specific criteria are in § 1.6.9(P)(2) of this Part.
Toolbox Option	Cryptosporidium treatment credit with design and implementation criteria
Pre-Filtration Toolbox Options
(3) Presedimentation basin with coagulation	0.5-log credit during any month that presedimentation basins achieve a monthly mean reduction of 0.5-log or greater in turbidity or alternative Director-approved performance criteria. To be eligible, basins must be operated continuously with coagulant addition and all plant flow must pass through basins. Specific criteria are in § 1.6.9(Q)(1) of this Part.
(4) Two-stage lime softening	0.5-log credit for two-stage softening where chemical addition and hardness precipitation occur in both stages. All plant flow must pass through both stages. Single-stage softening is credited as equivalent to conventional treatment. Specific criteria are in § 1.6.9(Q)(2) of this Part.
(5) Bank filtration	0.5-log credit for 25-foot setback; 1.0-log credit for 50-foot setback; aquifer must be unconsolidated sand containing at least 10 percent fines; average turbidity in wells must be less than 1 NTU. PWSs using wells followed by filtration when conducting source water monitoring must sample the well to determine bin classification and are not eligible for additional credit. Specific criteria are in § 1.6.9(Q)(3) of this Part.
Treatment Performance Toolbox Options
(6) Combined filter performance	0.5-log credit for combined filter effluent turbidity less than or equal to 0.15 NTU in at least 95 percent of measurements each month. Specific criteria are in § 1.6.9(R)(1) of this Part.
(7) Individual filter performance	0.5-log credit (in addition to 0.5-log combined filter performance credit) if individual filter effluent turbidity is less than or equal to 0.15 NTU in at least 95 percent of samples each month in each filter and is never greater than 0.3 NTU in two consecutive measurements in any filter. Specific criteria are in § 1.6.9(R)(2) of this Part.
(8) Demonstration of performance	Credit awarded to unit process or treatment train based on a demonstration to the Director with a Director-approved protocol. Specific criteria are in § 1.6.9(R)(3) of this Part.
Toolbox Option	Cryptosporidium treatment credit with design and implementation criteria
Additional Filtration Toolbox Options
(9) Bag or cartridge filters (individual filters)	Up to 2-log credit based on the removal efficiency demonstrated during challenge testing with a 1.0-log factor of safety. Specific criteria are in § 1.6.9(S)(1) of this Part.
(10) Bag or cartridge filters (in series)	Up to 2.5-log credit based on the removal efficiency demonstrated during challenge testing with a 0.5-log factor of safety. Specific criteria are in § 1.6.9(S)(1) of this Part.
(11) Membrane filtration	Log credit equivalent to removal efficiency demonstrated in challenge test for device if supported by direct integrity testing. Specific criteria are in § 1.6.9(S)(2) of this Part.
(12) Second stage filtration	0.5-log credit for second separate granular media filtration stage if treatment train includes coagulation prior to first filter. Specific criteria are in § 1.6.9(S)(3) of this Part.
(13) Slow sand filters	2.5-log credit as a secondary filtration step; 3.0-log credit as a primary filtration process. No prior chlorination for either option. Specific criteria are in § 1.6.9(S)(4) of this Part.
Inactivation Toolbox Options
(14) Chlorine dioxide	Log credit based on measured CT in relation to CT table. Specific criteria in § 1.6.9(T)(2) of this Part.
(15) Ozone	Log credit based on measured CT in relation to CT table. Specific criteria in § 1.6.9(T)(2) of this Part.
(16) UV	Log credit based on validated UV dose in relation to UV dose table; reactor validation testing required to establish UV dose and associated operating conditions. Specific criteria in § 1.6.9(T)(4) of this Part.

P. Source Toolbox Components

1. Watershed Control Program. PWSs receive 0.5-log Cryptosporidium treatment credit for implementing a watershed control program that meets the requirements of this Section.

a. PWSs that intend to apply for the watershed control program credit must notify the Director of this intent no later than two years prior to the treatment compliance date applicable to the PWS in § 1.6.9(N) of this Part.

b. PWSs must submit to the Director a proposed watershed control plan no later than one year before the applicable treatment compliance date in § 1.6.9(N) of this Part. The Director must approve the watershed control plan for the PWS to receive watershed control program treatment credit. The watershed control plan must include the elements in §§ 1.6.9(P)(1)(b) ((1)) through ((4)) of this Part.

(1) Identification of an "area of influence" outside of which the likelihood of Cryptosporidium or fecal contamination affecting the treatment plant intake is not significant. This is the area to be evaluated in future watershed surveys under § 1.6.9(P)(1)(e) ((2)) of this Part.

(2) Identification of both potential and actual sources of Cryptosporidium contamination and an assessment of the relative impact of these sources on the PWS's source water quality.

(3) An analysis of the effectiveness and feasibility of control measures that could reduce Cryptosporidium loading from sources of contamination to the PWS's source water.

(4) A statement of goals and specific actions the PWS will undertake to reduce source water Cryptosporidium levels. The plan must explain how the actions are expected to contribute to specific goals, identify watershed partners and their roles, identify resource requirements and commitments, and include a schedule for plan implementation with deadlines for completing specific actions identified in the plan.

c. PWSs with existing watershed control programs are eligible to seek this credit. Their watershed control plans must meet the criteria in § 1.6.9(P)(1)(b) of this Part, and must specify ongoing and future actions that will reduce source water Cryptosporidium levels.

d. If the Director does not respond to a PWS regarding approval of a watershed control plan submitted under this Section and the PWS meets the other requirements of this Section, the watershed control program will be considered approved and 0.5 log Cryptosporidium treatment credit will be awarded unless and until the Director subsequently withdraws such approval.

e. PWSs must complete the actions in §§ 1.6.9(P)(1)(e) ((1)) through ((3)) of this Part to maintain the 0.5-log credit.

(1) Submit an annual watershed control program status report to the Director. The annual watershed control program status report must describe the PWS's implementation of the approved plan and assess the adequacy of the plan to meet its goals. It must explain how the PWS is addressing any shortcomings in plan implementation, including those previously identified by the Director or as the result of the watershed survey conducted under § 1.6.9(P)(1)(e) ((2)) of this Part. It must also describe any significant changes that have occurred in the watershed since the last watershed sanitary survey. If a PWS determines during implementation that making a significant change to its approved watershed control program is necessary, the PWS must notify the Director prior to making any such changes. If any change is likely to reduce the level of source water protection, the PWS must also list in its notification the actions the PWS will take to mitigate this effect.

(2) Undergo a watershed sanitary survey every three years for community PWS and every five years for noncommunity PWS and submit the survey report to the Director. The survey must be conducted according to the Director's guidelines and by persons the Director approves.

(AA) The watershed sanitary survey must meet the following criteria: encompass the region identified in the Director-approved watershed control plan as the area of influence; assess the implementation of actions to reduce source water Cryptosporidium levels; and identify any significant new sources of Cryptosporidium.

(BB) If the Director determines that significant changes may have occurred in the watershed since the previous watershed sanitary survey, PWSs must undergo another watershed sanitary survey by a date the Director requires, which may be earlier than the regular date in § 1.6.9(P)(1)(e) ((2)) of this Part.

(3) The PWS must make the watershed control plan, annual status reports, and watershed sanitary survey reports available to the public upon request. These documents must be in a plain language style and include criteria by which to evaluate the success of the program in achieving plan goals. The Director may approve PWSs to withhold from the public portions of the annual status report, watershed control plan, and watershed sanitary survey based on water supply security considerations.

f. If the Director determines that a PWS is not carrying out the approved watershed control plan, the Director may withdraw the watershed control program treatment credit.

2. Alternative Source

a. A PWS may conduct source water monitoring that reflects a different intake location (either in the same source or for an alternate source) or a different procedure for the timing or level of withdrawal from the source (alternative source monitoring). If the Director approves, a PWS may determine its bin classification under § 1.6.9(K) of this Part based on the alternative source monitoring results.

b. If PWSs conduct alternative source monitoring under § 1.6.9(P)(2)(a) of this Part, PWSs must also monitor their current plant intake concurrently as described in § 1.6.9(B) of this Part.

c. Alternative source monitoring under § 1.6.9(P)(2)(a) of this Part must meet the requirements for source monitoring to determine bin classification, as described in §§ 1.6.9(B) through (G) of this Part. PWSs must report the alternative source monitoring results to the Director, along with supporting information documenting the operating conditions under which the samples were collected.

d. If a PWS determines its bin classification under § 1.6.9(K) of this Part using alternative source monitoring results that reflect a different intake location or a different procedure for managing the timing or level of withdrawal from the source, the PWS must relocate the intake or permanently adopt the withdrawal procedure, as applicable, no later than the applicable treatment compliance date in § 1.6.9(N) of this Part.

Q. Pre-Filtration Treatment Toolbox Components

1. Presedimentation. PWSs receive 0.5-log Cryptosporidium treatment credit for a presedimentation basin during any month the process meets the criteria in this paragraph.

a. The presedimentation basin must be in continuous operation and must treat the entire plant flow taken from a surface water or GWUDI source.

b. The PWS must continuously add a coagulant to the presedimentation basin.

c. The presedimentation basin must achieve the performance criteria in § 1.6.9(Q)(1)(c) ((1)) or ((2)) of this Part.

(1) Demonstrates at least 0.5-log mean reduction of influent turbidity. This reduction must be determined using daily turbidity measurements in the presedimentation process influent and effluent and must be calculated as follows: log10(monthly mean of daily influent turbidity-log10(monthly mean of daily effluent turbidity).

(2) Complies with Director-approved performance criteria that demonstrate at least 0.5-log mean removal of micron-sized particulate material through the presedimentation process.

2. Two-Stage Lime Softening. PWSs receive an additional 0.5-log Cryptosporidium treatment credit for a two-stage lime softening plant if chemical addition and hardness precipitation occur in two separate and sequential softening stages prior to filtration. Both softening stages must treat the entire plant flow taken from a surface water or GWUDI source.

3. Bank Filtration. PWSs receive Cryptosporidium treatment credit for bank filtration that serves as pretreatment to a filtration plant by meeting the criteria in this paragraph. PWSs using bank filtration when they begin source water monitoring under § 1.6.9(B)(1) of this Part must collect samples as described in § 1.6.9(D)(4) of this Part, and are not eligible for this credit.

a. Wells with a groundwater flow path of at least twenty-five (25) feet receive 0.5-log treatment credit; wells with a groundwater flow path of at least fifty (50) feet receive 1.0-log treatment credit. The groundwater flow path must be determined as specified in § 1.6.9(Q)(3)(d) of this Part.

b. Only wells in granular aquifers are eligible for treatment credit. Granular aquifers are those comprised of sand, clay, silt, rock fragments, pebbles or larger particles, and minor cement. A PWS must characterize the aquifer at the well site to determine aquifer properties. PWSs must extract a core from the aquifer and demonstrate that in at least ninety percent (90%) of the core length, grains less than 1.0 mm in diameter constitute at least ten percent (10%) of the core material.

c. Only horizontal and vertical wells are eligible for treatment credit.

d. For vertical wells, the groundwater flow path is the measured distance from the edge of the surface water body under high flow conditions (determined by the 100-year floodplain elevation boundary or by the floodway, as defined in Federal Emergency Management Agency flood hazard maps) to the well screen. For horizontal wells, the groundwater flow path is the measured distance from the bed of the river under normal flow conditions to the closest horizontal well lateral screen.

e. PWSs must monitor each wellhead for turbidity at least once every four hours while the bank filtration process is in operation. If monthly average turbidity levels, based on daily maximum values in the well, exceed 1 NTU, the PWS must report this result to the Director and conduct an assessment within thirty (30) days to determine the cause of the high turbidity levels in the well. If the Director determines that microbial removal has been compromised, the Director may revoke treatment credit until the PWS implements corrective actions approved by the Director to remediate the problem.

f. Springs and infiltration galleries are not eligible for treatment credit under this Section, but are eligible for credit under § 1.6.9(R)(3) of this Part.

g. Bank Filtration Demonstration of Performance. The Director may approve Cryptosporidium treatment credit for bank filtration based on a demonstration of performance study that meets the criteria in this paragraph. This treatment credit may be greater than 1.0-log and may be awarded to bank filtration that does not meet the criteria in §§ 1.6.9(Q)(3)(a) through (e) of this Part.

(1) The study must follow a Director-approved protocol and must involve the collection of data on the removal of Cryptosporidium or a surrogate for Cryptosporidium and related hydrogeologic and water quality parameters during the full range of operating conditions.

(2) The study must include sampling both from the production well(s) and from monitoring wells that are screened and located along the shortest flow path between the surface water source and the production well(s).

R. Treatment Performance Toolbox Components

1. Combined filter performance. PWSs using conventional filtration treatment or direct filtration treatment receive an additional 0.5-log Cryptosporidium treatment credit during any month the PWS meets the criteria in this paragraph. Combined filter effluent (CFE) turbidity must be less than or equal to 0.15 NTU in at least 95 percent of the measurements. Turbidity must be measured as described in § 1.21 of this Part.

2. Individual filter performance. PWSs using conventional filtration treatment or direct filtration treatment receive 0.5-log Cryptosporidium treatment credit, which can be in addition to the 0.5-log credit under § 1.6.9(R)(1) of this Part, during any month the PWS meets the criteria in this paragraph. Compliance with these criteria must be based on individual filter turbidity monitoring as described in § 1.6.7 of this Part, as applicable.

a. The filtered water turbidity for each individual filter must be less than or equal to 0.15 NTU in at least 95 percent of the measurements recorded each month.

b. No individual filter may have a measured turbidity greater than 0.3 NTU in two consecutive measurements taken fifteen (15) minutes apart.

c. Any PWS that has received treatment credit for individual filter performance and fails to meet the requirements of §§ 1.6.9(R)(2)(a) or (b) of this Part during any month does not receive a treatment technique violation under § 1.6.9(L)(3) of this Part, if the Director determines the following:

(1) The failure was due to unusual and short-term circumstances that could not reasonably be prevented through optimizing treatment plant design, operation, and maintenance.

(2) The PWS has experienced no more than two such failures in any calendar year.

3. Demonstration of Performance. The Director may approve Cryptosporidium treatment credit for drinking water treatment processes based on a demonstration of performance study that meets the criteria in this paragraph. This treatment credit may be greater than or less than the prescribed treatment credits in § 1.6.9(L) or §§ 1.6.9(Q) through (T) of this Part, and may be awarded to treatment processes that do not meet the criteria for the prescribed credits.

a. PWSs cannot receive the prescribed treatment credit for any toolbox box option in §§ 1.6.9(Q) through (T) of this Part, if that toolbox option is included in a demonstration of performance study for which treatment credit is awarded under this paragraph.

b. The demonstration of performance study must follow a Director-approved protocol and must demonstrate the level of Cryptosporidium reduction the treatment process will achieve under the full range of expected operating conditions for the PWS.

c. Approval by the Director must be in writing and may include monitoring and treatment performance criteria that the PWS must demonstrate and report on an ongoing basis to remain eligible for the treatment credit. The Director may designate such criteria where necessary to verify that the conditions under which the demonstration of performance credit was approved are maintained during routine operation.

S. Additional Filtration Toolbox Components

1. Bag and Cartridge Filters. PWSs receive Cryptosporidium treatment credit of up to 2.0-log for individual bag or cartridge filters and up to 2.5-log for bag or cartridge filters operated in series by meeting the criteria in §§ 1.6.9(S)(1)(a) through (j) of this Part. To be eligible for this credit, PWSs must report the results of challenge testing that meets the requirements of §§ 1.6.9(S)(1)(b) through (i) of this Part to the Director. The filters must treat the entire plant flow taken from a § 1.6 source.

a. The Cryptosporidium treatment credit awarded to bag or cartridge filters must be based on the removal efficiency demonstrated during challenge testing that is conducted according to the criteria in §§ 1.6.9(S)(1)(b) through (i) of this Part. A factor of safety equal to 1-log for individual bag or cartridge filters and 0.5-log for bag or cartridge filters in series must be applied to challenge testing results to determine removal credit. PWSs may use results from challenge testing conducted prior to January 5, 2006 if the prior testing was consistent with the criteria specified in §§ 1.6.9(S)(1)(b) through (i) of this Part.

b. Challenge testing must be performed on full-scale bag or cartridge filters, and the associated filter housing or pressure vessel, that are identical in material and construction to the filters and housings the PWS will use for removal of Cryptosporidium. Bag or cartridge filters must be challenge tested in the same configuration that the PWS will use, either as individual filters or as a series configuration of filters.

c. Challenge testing must be conducted using Cryptosporidium or a surrogate that is removed no more efficiently than Cryptosporidium. The microorganism or surrogate used during challenge testing is referred to as the challenge particulate. The concentration of the challenge particulate must be determined using a method capable of discreetly quantifying the specific microorganism or surrogate used in the test; gross measurements such as turbidity may not be used.

d. The maximum feed water concentration that can be used during a challenge test must be based on the detection limit of the challenge particulate in the filtrate (i.e., filtrate detection limit) and must be calculated using the following equation:

(1) Maximum Feed Concentration = 1 x 10⁴ x (Filtrate Detection Limit)

e. Challenge testing must be conducted at the maximum design flow rate for the filter as specified by the manufacturer.

f. Each filter evaluated must be tested for a duration sufficient to reach one hundred percent (100%) of the terminal pressure drop, which establishes the maximum pressure drop under which the filter may be used to comply with the requirements of § 1.6.9 of this Part.

g. Removal efficiency of a filter must be determined from the results of the challenge test and expressed in terms of log removal values using the following equation:

Click here to view image

Where:

LRV = Log removal value demonstrated during challenge testing;

C_f = The feed concentration measured during the challenge test; and

C_p = The filtrate concentration measured during the challenge test.

(1) In applying this equation, the same units must be used for the feed and filtrate concentrations. If the challenge particulate is not detected in the filtrate, then the term Cp must be set equal to the detection limit.

h. Each filter tested must be challenged with the challenge particulate during three periods over the filtration cycle: within two hours of start-up of a new filter; when the pressure drop is between forty-five (45%) and fifty-five (55%) percent of the terminal pressure drop; and at the end of the cycle after the pressure drop has reached one hundred percent (100%) of the terminal pressure drop. An LRV must be calculated for each of these challenge periods for each filter tested. The LRV for the filter (LRVfilter) must be assigned the value of the minimum LRV observed during the three challenge periods for that filter.

i. If fewer than twenty (20) filters are tested, the overall removal efficiency for the filter product line must be set equal to the lowest LRVfilter among the filters tested. If twenty (20) or more filters are tested, the overall removal efficiency for the filter product line must be set equal to the 10th percentile of the set of LRVfilter values for the various filters tested. The percentile is defined by (i/(n+1)) where i is the rank of n individual data points ordered lowest to highest. If necessary, the 10th percentile may be calculated using linear interpolation.

j. If a previously tested filter is modified in a manner that could change the removal efficiency of the filter product line, challenge testing to demonstrate the removal efficiency of the modified filter must be conducted and submitted to the Director.

2. Membrane Filtration

a. PWSs receive Cryptosporidium treatment credit for membrane filtration that meets the criteria of this paragraph. Membrane cartridge filters that meet the definition of membrane filtration in § 1.2 of this Part are eligible for this credit. The level of treatment credit a PWS receives is equal to the lower of the values determined under §§ 1.6.9(S)(2)(a) ((1)) and ((2)) of this Part.

(1) The removal efficiency demonstrated during challenge testing conducted under the conditions in § 1.6.9(S)(2)(b) of this Part.

(2) The maximum removal efficiency that can be verified through direct integrity testing used with the membrane filtration process under the conditions in § 1.6.9(S)(2)(c) of this Part.

b. Challenge Testing. The membrane used by the PWS must undergo challenge testing to evaluate removal efficiency, and the PWS must report the results of challenge testing to the Director. Challenge testing must be conducted according to the criteria in §§ 1.6.9(S)(2)(b) ((1)) through ((7)) of this Part. PWSs may use data from challenge testing conducted prior to January 5, 2006 if the prior testing was consistent with the criteria in §§ 1.6.9(S)(2)(b) ((1)) through ((7)) of this Part.

(1) Challenge testing must be conducted on either a full-scale membrane module, identical in material and construction to the membrane modules used in the PWS's treatment facility, or a smaller-scale membrane module, identical in material and similar in construction to the full-scale module. A module is defined as the smallest component of a membrane unit in which a specific membrane surface area is housed in a device with a filtrate outlet structure.

(2) Challenge testing must be conducted using Cryptosporidium oocysts or a surrogate that is removed no more efficiently than Cryptosporidium oocysts. The organism or surrogate used during challenge testing is referred to as the challenge particulate. The concentration of the challenge particulate, in both the feed and filtrate water, must be determined using a method capable of discretely quantifying the specific challenge particulate used in the test; gross measurements such as turbidity may not be used.

(3) The maximum feed water concentration that can be used during a challenge test is based on the detection limit of the challenge particulate in the filtrate and must be determined according to the following equation:

(AA) Maximum Feed Concentration = 3.16 x 106 x (Filtrate Detection Limit)

(4) Challenge testing must be conducted under representative hydraulic conditions at the maximum design flux and maximum design process recovery specified by the manufacturer for the membrane module. Flux is defined as the throughput of a pressure driven membrane process expressed as flow per unit of membrane area. Recovery is defined as the volumetric percent of feed water that is converted to filtrate over the course of an operating cycle uninterrupted by events such as chemical cleaning or a solids removal process (i.e., backwashing).

(5) Removal efficiency of a membrane module must be calculated from the challenge test results and expressed as a log removal value according to the following equation:

Click here to view image

Where:

LRV = Log removal value demonstrated during challenge test;

C_f = The feed concentration measured during the challenge test; and

C_p = The filtrate concentration measured during the challenge test.

(AA) Equivalent units must be used for the feed and filtrate concentrations. If the challenge particulate is not detected in the filtrate, then the term Cp is be set equal to the detection limit for the purpose of calculating the LRV. An LRV must be calculated for each membrane module evaluated during the challenge test.

(6) The removal efficiency of a membrane filtration process demonstrated during challenge testing must be expressed as a log removal value (LRVC-Test). If fewer than twenty (20) modules are tested, then LRVC-Test is equal to the lowest of the representative LRVs among the modules tested. If twenty (20) or more modules are tested, then LRVC-Test is equal to the 10th percentile of the representative LRVs among the modules tested. The percentile is defined by (i/(n+1)) where i is the rank of n individual data points ordered lowest to highest. If necessary, the 10th percentile may be calculated using linear interpolation.

(7) The challenge test must establish a quality control release value (QCRV) for a non-destructive performance test that demonstrates the Cryptosporidium removal capability of the membrane filtration module. This performance test must be applied to each production membrane module used by the PWS that was not directly challenge tested in order to verify Cryptosporidium removal capability. Production modules that do not meet the established QCRV are not eligible for the treatment credit demonstrated during the challenge test.

(8) If a previously tested membrane is modified in a manner that could change the removal efficiency of the membrane or the applicability of the non-destructive performance test and associated QCRV, additional challenge testing to demonstrate the removal efficiency of, and determine a new QCRV for, the modified membrane must be conducted and submitted to the Director.

c. Direct Integrity Testing. PWSs must conduct direct integrity testing in a manner that demonstrates a removal efficiency equal to or greater than the removal credit awarded to the membrane filtration process and meets the requirements described in §§ 1.6.9(S)(2)(c) ((1)) through ((6)) of this Part. A direct integrity test is defined as a physical test applied to a membrane unit in order to identify and isolate integrity breaches (i.e., one or more leaks that could result in contamination of the filtrate).

(1) The direct integrity test must be independently applied to each membrane unit in service. A membrane unit is defined as a group of membrane modules that share common valving that allows the unit to be isolated from the rest of the PWS for the purpose of integrity testing or other maintenance.

(2) The direct integrity method must have a resolution of three (3) micrometers or less, where resolution is defined as the size of the smallest integrity breach that contributes to a response from the direct integrity test.

(3) The direct integrity test must have a sensitivity sufficient to verify the log treatment credit awarded to the membrane filtration process by the Director, where sensitivity is defined as the maximum log removal value that can be reliably verified by a direct integrity test. Sensitivity must be determined using the approach in either §§ 1.6.9(S)(2)(c) ((3))((AA)) or ((BB)) of this Part as applicable to the type of direct integrity test the PWS uses.

(AA) For direct integrity tests that use an applied pressure or vacuum, the direct integrity test sensitivity must be calculated according to the following equation:

Click here to view image

Where:

LRV_DIT = The sensitivity of the direct integrity test;

Q_p = Total design filtrate flow from the membrane unit;

Q_breach = Flow of water from an integrity breach associated with the smallest integrity test response that can be reliably measured, and

VCF = Volumetric concentration factor.

The volumetric concentration factor is the ratio of the suspended solids concentration on the high-pressure side of the membrane relative to that in the feed water.

(BB) For direct integrity tests that use a particulate or molecular marker, the direct integrity test sensitivity must be calculated according to the following equation:

Click here to view image

Where:

LRV_DIT = The sensitivity of the direct integrity test;

C_f = The typical feed concentration of the marker used in the test; and

C_p = The filtrate concentration of the marker from an integral membrane unit.

(4) PWSs must establish a control limit within the sensitivity limits of the direct integrity test that is indicative of an integral membrane unit capable of meeting the removal credit awarded by the Director.

(5) If the result of a direct integrity test exceeds the control limit established under § 1.6.9(S)(2)(c) ((4)) of this Part, the PWS must remove the membrane unit from service. PWSs must conduct a direct integrity test to verify any repairs, and may return the membrane unit to service only if the direct integrity test is within the established control limit.

(6) PWSs must conduct direct integrity testing on each membrane unit at a frequency of not less than once each day that the membrane unit is in operation. The Director may approve less frequent testing, based on demonstrated process reliability, the use of multiple barriers effective for Cryptosporidium, or reliable process safeguards.

d. Indirect Integrity Monitoring. PWSs must conduct continuous indirect integrity monitoring on each membrane unit according to the criteria in §§ 1.6.9(S)(2)(d) ((1)) through ((5)) of this Part. Indirect integrity monitoring is defined as monitoring some aspect of filtrate water quality that is indicative of the removal of particulate matter. A PWS that implements continuous direct integrity testing of membrane units in accordance with the criteria in §§ 1.6.9(S)(2)(c) ((1)) through ((5)) of this Part is not subject to the requirements for continuous indirect integrity monitoring. PWSs must submit a monthly report to the Director summarizing all continuous indirect integrity monitoring results triggering direct integrity testing and the corrective action that was taken in each case.

(1) Unless the Director approves an alternative parameter, continuous indirect integrity monitoring must include continuous filtrate turbidity monitoring.

(2) Continuous monitoring must be conducted at a frequency of no less than once every fifteen (15) minutes.

(3) Continuous monitoring must be separately conducted on each membrane unit.

(4) If indirect integrity monitoring includes turbidity and if the filtrate turbidity readings are above 0.15 NTU for a period greater than fifteen (15) minutes (i.e., two consecutive 15-minute readings above 0.15 NTU), direct integrity testing must immediately be performed on the associated membrane unit as specified in §§ 1.6.9(S)(2)(c) ((1)) through ((5)) of this Part.

(5) If indirect integrity monitoring includes a Director-approved alternative parameter and if the alternative parameter exceeds a Director-approved control limit for a period greater than fifteen (15) minutes, direct integrity testing must immediately be performed on the associated membrane units as specified in §§ 1.6.9(S)(2)(c) ((1)) through ((5)) of this Part.

3. Second Stage Filtration. PWSs receive 0.5-log Cryptosporidium treatment credit for a separate second stage of filtration that consists of sand, dual media, GAC, or other fine grain media following granular media filtration if the Director approves. To be eligible for this credit, the first stage of filtration must be preceded by a coagulation step and both filtration stages must treat the entire plant flow taken from a surface water or GWUDI source. A cap, such as GAC, on a single stage of filtration is not eligible for this credit. The Director must approve the treatment credit based on an assessment of the design characteristics of the filtration process.

4. Slow Sand Filtration (as secondary filter). PWSs are eligible to receive 2.5-log Cryptosporidium treatment credit for a slow sand filtration process that follows a separate stage of filtration if both filtration stages treat entire plant flow taken from a surface water or GWUDI source and no disinfectant residual is present in the influent water to the slow sand filtration process. The Director must approve the treatment credit based on an assessment of the design characteristics of the filtration process. This paragraph does not apply to treatment credit awarded to slow sand filtration used as a primary filtration process.

T. Inactivation Toolbox Components

1. Calculation of CT Values

a. CT is the product of the disinfectant contact time (T, in minutes) and disinfectant concentration (C, in milligrams per liter). PWSs with treatment credit for chlorine dioxide or ozone under §§ 1.6.9(T)(2) or (3) of this Part must calculate CT at least once each day, with both C and T measured during peak hourly flow as specified in § 1.21 of this Part.

b. PWSs with several disinfection segments in sequence may calculate CT for each segment, where a disinfection segment is defined as a treatment unit process with a measurable disinfectant residual level and a liquid volume. Under this approach, PWSs must add the Cryptosporidium CT values in each segment to determine the total CT for the treatment plant.

2. CT Values for Chlorine Dioxide and Ozone.

a. PWSs receive the Cryptosporidium treatment credit listed in this table by meeting the corresponding chlorine dioxide CT value for the applicable water temperature, as described in § 1.6.9(T)(1) of this Part.

CT Values (mg·min/L) for Cryptosporidium Inactivation by Chlorine Dioxide⁸
Log credit	Water Temperature, ºC
Log credit	[LESS THAN OR EQUAL TO] 0.5	1	2	3	5	7	10	15	20	25	30
(i) 0.25	159	153	140	128	107	90	69	45	29	19	12
(ii) 0.5	319	305	279	256	214	180	138	89	58	38	24
(iii) 1.0	637	610	558	511	429	360	277	179	116	75	49
(iv) 1.5	956	915	838	767	643	539	415	268	174	113	73
(v) 2.0	1275	1220	1117	1023	858	719	553	357	232	150	98
(vi) 2.5	1594	1525	1396	1278	1072	899	691	447	289	188	122
(vii) 3.0	1912	1830	1675	1534	1286	1079	830	536	347	226	147
⁸ Systems may use this equation to determine log credit between the indicated values: Log credit = (0.001506 x (1.09116)Temp) x CT.

b. PWSs receive the Cryptosporidium treatment credit listed in this table by meeting the corresponding ozone CT values for the applicable water temperature, as described in § 1.6.9(T)(1) of this Part.

CT Values (mg·min/L) for Cryptosporidium Inactivation by Ozone⁹
Log credit	Water Temperature, ºC
Log credit	[LESS THAN OR EQUAL TO] 0.5	1	2	3	5	7	10	15	20	25	30
(i) 0.25	6.0	5.8	5.2	4.8	4.0	3.3	2.5	1.6	1.0	0.6	0.39
(ii) 0.5	12	12	10	9.5	7.9	6.5	4.9	3.1	2.0	1.2	0.78
(iii) 1.0	24	23	21	19	16	13	9.9	6.2	3.9	2.5	1.6
(iv) 1.5	36	35	31	29	24	20	15	9.3	5.9	3.7	2.4
(v) 2.0.	48	46	42	38	32	26	20	12	7.8	4.9	3.1
(vi) 2.5	60	58	52	48	40	33	25	16	9.8	6.2	3.9
(vii) 3.0	72	69	63	57	47	39	30	19	12	7.4	4.7
⁹ Systems may use this equation to determine log credit between the indicated values: Log credit = (0.0397 x (1.09757)^Temp) x CT.

3. Site-Specific Study. The Director may approve alternative chlorine dioxide or ozone CT values to those listed in § 1.6.9(T)(2) of this Part on a site- specific basis. The Director must base this approval on a site-specific study a PWS conducts that follows a Director-approved protocol.

4. Ultraviolet Light. PWSs receive Cryptosporidium, Giardia lamblia, and virus treatment credits for ultraviolet (UV) light reactors by achieving the corresponding UV dose values shown in § 1.6.9(T)(4)(a) of this Part. PWSs must validate and monitor UV reactors as described in § 1.6.9(T)(4)(b) and (c) of this Part to demonstrate that they are achieving a particular UV dose value for treatment credit.

a. UV Dose Table. The treatment credits listed in this table are for UV light at a wavelength of 254 nm as produced by a low-pressure mercury vapor lamp. To receive treatment credit for other lamp types, PWSs must demonstrate an equivalent germicidal dose through reactor validation testing, as described in § 1.6.9(T)(4)(b) of this Part. The UV dose values in this table are applicable only to post-filter applications of UV in filtered PWSs and to unfiltered PWSs.

UV Dose Table for Cryptosporidium, Giardia lamblia, and Virus Inactivation Credit
Log credit	Cryptosporidium UV dose (mJ/cm²)	Giardia lamblia UV dose (mJ/cm²)	Virus UV dose (mJ/cm²)
(i) 0.5	1.6	1.5	39
(ii) 1.0	2.5	2.1	58
(iii) 1.5	3.9	3.0	79
(iv) 2.0	5.8	5.2	100
(v) 2.5.	8.5	7.7	121
(vi) 3.0	12	11	143
(vii) 3.5	15	15	163
(viii) 4.0	22	22	186

b. Reactor Validation Testing. PWSs must use UV reactors that have undergone validation testing to determine the operating conditions under which the reactor delivers the UV dose required in § 1.6.9(T)(4)(a) of this Part (i.e., validated operating conditions).

(1) When determining validated operating conditions, PWSs must account for the following factors: UV absorbance of the water; lamp fouling and aging; measurement uncertainty of on-line sensors; UV dose distributions arising from the velocity profiles through the reactor; failure of UV lamps or other critical PWS components; and inlet and outlet piping or channel configurations of the UV reactor.

(2) Validation testing must include the following: Full scale testing of a reactor that conforms uniformly to the UV reactors used by the PWS and inactivation of a test microorganism whose dose response characteristics have been quantified with a low-pressure mercury vapor lamp.

(3) The Director may approve an alternative approach to validation testing.

c. Reactor Monitoring

(1) PWSs must monitor their UV reactors to determine if the reactors are operating within validated conditions, as determined under § 1.6.9(T)(4)(b) of this Part. This monitoring must include UV intensity as measured by a UV sensor, flow rate, lamp status, and other parameters the State designates based on UV reactor operation. PWSs must verify the calibration of UV sensors and must recalibrate sensors in accordance with a protocol the Director approves.

(2) To receive treatment credit for UV light, PWSs must treat at least 95 percent of the water delivered to the public during each month by UV reactors operating within validated conditions for the required UV dose, as described in §§ 1.6.9(T)(4)(a) and (b) of this Part. PWSs must demonstrate compliance with this condition by the monitoring required under § 1.6.9(T)(4)(c) ((1)) of this Part.

U. Reporting Requirements

1. PWSs must report sampling schedules under § 1.6.9(C) of this Part and source water monitoring results under § 1.6.9(G) of this Part unless they notify the Director that they will not conduct source water monitoring due to meeting the criteria of § 1.6.9(B)(4) of this Part.

2. Filtered PWSs must report their Cryptosporidium bin classification as described in § 1.6.9(K) of this Part.

3. Unfiltered PWSs must report their mean source water Cryptosporidium level as described in § 1.6.9(M) of this Part.

4. PWSs must report disinfection profiles and benchmarks to the Director as described in §§ 1.6.9(I) through (J) of this Part prior to making a significant change in disinfection practice.

5. PWSs must report to the Director in accordance with the following table for any microbial toolbox options used to comply with treatment requirements under §§ 1.6.9(L) or 1.6.9(M) of this Part. Alternatively, the Director may approve a PWS to certify operation within required parameters for treatment credit rather than reporting monthly operational data for toolbox options.

MICROBIAL TOOLBOX REPORTING REQUIREMENTS
Toolbox option	PWSs must submit the following information	On the following schedule
(1) Watershed control program (WCP)	(i) Notice of intention to develop a new or continue an existing watershed control program	No later than two (2) years before the applicable treatment compliance date in § 1.6.9(N) of this Part.
	(ii) Watershed control plan	No later than one (1) year before the applicable treatment compliance date in § 1.6.9(N) of this Part.
	(iii) Annual watershed control program status report	Every twelve (12) months, beginning one (1) year after the applicable treatment compliance date in § 1.6.9(N) of this Part.
	(iv) Watershed sanitary survey report	For community PWS, every three (3) years beginning three (3) years after the applicable treatment compliance date in § 1.6.9(N) of this Part. For noncommunity PWS, every five (5) years beginning five (5) years after the applicable treatment compliance date in § 1.6.9(N) of this Part.
(2) Alternative source/intake management	Verification that PWS has relocated the intake or adopted the intake withdrawal procedure reflected in monitoring results	No later than the applicable treatment compliance date in § 1.6.9(N) of this Part.
(3) Presedimentation	Monthly verification of the following: (i) Continuous basin operation (ii) Treatment of 100% of the flow (iii) Continuous addition of a coagulant (iv) At least 0.5-log mean reduction of influent turbidity or compliance with alternative State-approved performance criteria.	Monthly reporting within ten (10) days following the month in which the monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(4) Two-stage lime softening	Monthly verification of the following: (i) Chemical addition and hardness precipitation occurred in two separate and sequential softening stages prior to filtration (ii) Both stages treated 100% of the plant flow.	Monthly reporting within ten (10) days following the month in which the monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(5) Bank filtration	(i) Initial demonstration of the following: (A) Unconsolidated, predominantly sandy aquifer (B) Setback distance of at least 25 ft. (0.5-log credit) or 50 ft. (1.0-log credit).	No later than the applicable treatment compliance date in § 1.6.9(N) of this Part.
(5) Bank filtration	(ii) If monthly average of daily max turbidity is greater than 1 NTU then PWS must report result and submit an assessment of the cause.	Report within thirty (30) days following the month in which the monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(6) Combined filter performance	Monthly verification of combined filter effluent (CFE) turbidity levels less than or equal to 0.15 NTU in at least 95 percent of the 4-hour CFE measurements taken each month.	Monthly reporting within ten (10) days following the month in which the monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(7) Individual filter performance	Monthly verification of the following: (i) Individual filter effluent (IFE) turbidity levels less than or equal to 0.15 NTU in at least 95 percent of samples each month in each filter (ii) No individual filter greater than 0.3 NTU in two consecutive readings 15 minutes apart	Monthly reporting within ten (10) days following the month in which the monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(8) Demonstration of performance	(i) Results from testing following a State approved protocol. (ii) As required by the State, monthly verification of operation within conditions of State approval for demonstration of performance credit.	No later than the applicable treatment compliance date in § 1.6.9(N) of this Part. Within ten (10) days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(9) Bag filters and cartridge filters	(i) Demonstration that the following criteria are met: (A) Process meets the definition of bag or cartridge filtration; (B) Removal efficiency established through challenge testing that meets criteria in this subpart.	No later than the applicable treatment compliance date in § 1.6.9(N) of this Part.
(9) Bag filters and cartridge filters	(ii) Monthly verification that 100% of plant flow was filtered	Within ten (10) days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(10) Membrane filtration	(i) Results of verification testing demonstrating the following: (A) Removal efficiency established through challenge testing that meets criteria in this subpart; (B) Integrity test method and parameters, including resolution, sensitivity, test frequency, control limits, and associated baseline.	No later than the applicable treatment compliance date in § 1.6.9(N) of this Part.
	(ii) Monthly report summarizing the following: (A) All direct integrity tests above the control limit; (B) If applicable, any turbidity or alternative state approved indirect integrity monitoring results triggering direct integrity testing and the corrective action that was taken.	Within ten (10) days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(11) Second stage filtration	Monthly verification that 100% of flow was filtered through both stages and that first stage was preceded by coagulation step.	Within ten (10) days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(12) Slow sand filtration (as secondary filter)	Monthly verification that both a slow sand filter and a preceding separate stage of filtration treated 100% of flow from § 1.6 sources.	Within ten (10) days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.
(13) Chlorine dioxide	Summary of CT values for each day as described in § 1.6.9(T) of this Part.	Within ten (10) days following the month in which monitoring was conducted.
(14) Ozone	Summary of CT values for each day as described in § 1.6.9(T) of this Part.	Within ten (10) days following the month in which monitoring was conducted.
(15) UV	(i) Validation test results demonstrating operating	No later than the applicable treatment
	conditions that achieve required UV dose.	compliance date in § 1.6.9(N) of this Part.
	(ii) Monthly report summarizing the percentage of water entering the distribution system that was not treated by UV reactors operating within validated conditions for the required dose as specified in § 1.6.9(T)(4) of this Part.	Within ten (10) days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in § 1.6.9(N) of this Part.

V. Recordkeeping Requirements

1. PWSs must keep results from the initial round of source water monitoring under § 1.6.9(B)(1) of this Part and the second round of source water monitoring under § 1.6.9(B)(2) of this Part until three (3) years after bin classification under § 1.6.9(K) of this Part, for filtered PWSs or determination of the mean Cryptosporidium level under § 1.6.9(K) of this Part, for unfiltered PWSs for the particular round of monitoring.

2. PWSs must keep any notification to the Director that they will not conduct source water monitoring due to meeting the criteria of § 1.6.9(B)(4) of this Part, for three (3) years.

3. PWSs must keep the results of treatment monitoring associated with microbial toolbox options under §§ 1.6.9(P) through 1.6.9(T) of this Part as applicable, for three (3) years.

W. Requirements to Respond to Significant Deficiencies Identified in Sanitary Surveys Performed by the Director

1. For the purposes of this Section, a "sanitary survey," as conducted by the Director, includes but is not limited to, an onsite review of the water source(s) (identifying sources of contamination by using results of source water assessments or other relevant information where available), facilities, equipment, operation, maintenance, and monitoring compliance of a PWS to evaluate the adequacy of the PWS, its sources and operations and the distribution of safe drinking water. The sanitary survey must include an evaluation of the applicable components listed in § 1.6.9(W)(1)(a) through (h):

a. Source,

b. Treatment,

c. Distribution system,

d. Finished water storage,

e. Pumps, pump facilities, and controls,

f. Monitoring, reporting, and data verification,

g. PWS management and operation, and

h. Operator compliance with Director requirements.

2. For the purposes of this Section, significant deficiencies include, but are not limited to, defects in design, operation, or maintenance, or a failure or malfunction of the sources, treatment, storage, or distribution system that the Director determines to be causing, or have potential for causing, the introduction of contamination into the water delivered to consumers.

3. For sanitary surveys performed by the Director, PWSs must respond in writing to significant deficiencies identified in sanitary survey reports no later than forty-five (45) days after receipt of the report, indicating how and on what schedule the PWS will address significant deficiencies noted in the survey.

4. PWSs must correct significant deficiencies identified in sanitary survey reports according to the schedule approved by the Director, or if there is no approved schedule, according to the schedule reported under § 1.6.9(W)(3) above if such deficiencies are within the control of the PWS.

1.6.10Algal Toxins

A. Maximum Contaminant Levels (MCLs) for Algal Toxins

1. Microcystin: 0.3 micrograms per liter (µg/L), total concentration of all reported cogeners.

2. Anatoxin-a: 20 µg/L.

3. Cylindrospermopsin: 1 µg/L.

4. Saxitoxin: 0.2 µg/L, total concentration of all reported cogeners.

5. Exceedances of these MCLs in samples collected at finished water sampling point or a distribution sampling point will require additional monitoring, and potentially other actions as described in this Part.

B. Source Water Surveillance

1. Monitoring requirements are based on three levels of response: observation, screening, and algal toxin monitoring. Source waters shall be under increased observation for hazardous algal blooms (HABs) through direct surveillance by PWS personnel on a daily basis May through October, and at other times if so directed by the Director. Observations shall be recorded in a daily log and made available to the Director upon request.

2. If a PWS observes changes in raw source water commonly associated with an algal bloom (pH increase, shortened filter run times, increased chlorine demand, or taste and odor event), PWS personnel shall inspect the reservoir for visual evidence of a bloom to determine if cyanobacteria screening and/or algal toxin monitoring is required.

3. If a bloom is present, the PWS shall evaluate the extent of the reservoir affected, proximity of the bloom to the intake, depth of the intake, and treatment currently in use or available for use. Any available information on the algae conditions in the source waters, including algae identification, chlorophyll a, cell counts and biovolume, shall also be considered. In accordance with § 1.6.10(D) of this Part, the PWS shall determine if cyanobacteria screening or algal toxin monitoring must be initiated. If a source water is not being used as a source of supply while a bloom is present, then screening or monitoring shall not be required.

C. Bloom Severity

1. A bloom shall be described as severe, moderate, or minor based on cyanobacterial cell counts, biovolume, and other factors such as the presence of surface scum. Extent of the reservoir affected and proximity to the intake may also be considered. It may be necessary to make an initial assessment based on visual evidence, which can then be refined as additional information is collected. Since a severe bloom may not form a surface scum, in the absence of any additional data, a visible bloom shall be regarded as severe until additional data are collected.

2. Severe Bloom (meets any of the following):

a. Cell count greater than 70,000 cells /mL

b. Biovolume greater than 10 mm3 / L

c. Chlorophyll a* greater than 50 µg/L

d. Significant scum or surface accumulation is present and/or significant concentration of cells are visible throughout the water column

e. Presence of algal toxins as indicated by test kit or lab analysis

3. Moderate Bloom (meets any of the following):

a. Cell count 10,000-70,000 cells /mL

b. Biovolume 1-10 mm3 / L

c. Chlorophyll a* 5-50 µg/L

d. Minor scum or surface accumulation is present and/or bloom is visible throughout the water column

4. Minor Bloom (meets any of the following):

a. Cell count 4,000-10,000 cells /mL

b. Biovolume 0.4-1 mm3 / L

c. Chlorophyll a* 2-5 µg/L

d. Some visual evidence of a bloom*

5. *Chlorophyll-a values are based on quantitative in vitro analysis. Semi-quantitative in vivo chlorophyll-a readings can also be used if they have been corrected for turbidity effects. In some situations, a severe bloom may be present but not visually evident. It is always best to confirm a bloom is not present through microscopic analysis of a raw water source.

D. Algal Bloom Response Actions

1. The decision to continue observation, conduct screening or proceed to algal toxin monitoring shall be determined on a case by case basis after considering the following factors:

a. Severity of the bloom, location of the bloom, size of reservoir and extent of the reservoir affected;

b. Likelihood of cyanobacterial cells or algal toxins being drawn into the intake, including proximity of bloom to the intake, depth of intake and wind/weather conditions;

c. Whether advanced treatment is in use and working properly (e.g. granular activated carbon, powdered activated carbon, ozonation);

d. Whether the PWS has observed changes in raw water quality (e.g. taste and odor events or pH increases) associated with the presence of a bloom;

e. Reported human illness or animal death associated with a cyanobacterial bloom;

f. Results of screening indicating that algal toxins may be present at levels of concern in raw or finished water; and

g. History of algal toxin-producing blooms.

2. The following table shall be used when determining proper response action.

Bloom Severity	Likelihood of being drawn into the intake	Advanced Treatment	Action
Severe	More likely	Not in use or not working properly	Monitor for toxins weekly and observe daily
Severe	More likely	In use	Monitor for toxins weekly and observe daily
Severe	Less likely	Not in use or not working properly	Screen weekly and observe daily
Severe	Less likely	In use	Screen weekly and observe daily
Moderate	More likely	Not in use or not working properly	Monitor for Toxins weekly and observe daily
Moderate	More likely	In use	Screen weekly and observe daily
Moderate	Less likely	Not in use or not working properly	Screen weekly and observe daily
Moderate	Less likely	In use	Observe daily
Minor	More likely	Not in use or not working properly	Screen weekly and observe daily
Minor	More likely	In use	Observe daily
Minor	Less likely	Not in use or not working properly	Observe daily
Minor	Less likely	In use	Observe daily

3. Cyanobacteria Screening

a. When the proper response action consists of cyanobacteria screening, the PWS shall assess the algae conditions in its source waters using phytoplankton analysis for identification of cyanobacteria genera present, and cell count or biovolume information.

b. The PWS shall conduct screening at a minimum frequency of once per week while any of the following conditions occur:

(1) Observational information indicates that a bloom is present, but PWS is unable to determine the severity of the bloom, unless algal toxin monitoring is warranted;

(2) PWS observes changes in raw water quality (e.g. taste and odor evident in finished water or pH increases) associated with the presence of a bloom;

(3) Severe cyanobacterial bloom that is less likely to be drawn into the intake;

(4) Moderate cyanobacterial bloom that is less likely to be drawn into the intake at a PWS where there is no advanced treatment; and/or

(5) Moderate cyanobacterial bloom that is more likely to be drawn into the intake at a PWS where there is advanced treatment in operation.

c. Sample Location

(1) Phytoplankton samples shall be collected in the scum or biomass in areas where the bloom is concentrated.

4. Algal Toxin Monitoring

a. PWS shall conduct algal toxin monitoring when any of the following conditions occur:

(1) Severe cyanobacterial bloom that is more likely to be drawn into the intake;

(2) Moderate cyanobacterial bloom that is more likely to be drawn into the intake where advanced treatment is not in place or is not working properly;

(3) Reported human illness or animal death associated with a cyanobacterial bloom; and/or

(4) Results of screening indicate algal toxins may be present in raw or finished water.

b. Algal toxin monitoring shall include raw and finished water samples. The algal toxin testing shall include microcystin (total concentration of all reported cogeners), anatoxin-a, cylindrospermopsin and saxitoxin (total concentration of all reported cogeners). Additional toxin testing may be required by the Director on a case by case basis depending on the predominant genera and the toxins they can produce, and/or in the event of any reported health effects. Algal toxin monitoring shall continue weekly until algal toxins are less than fifty percent (50%) of the algal toxin MCL in both raw and finished water samples in two consecutive sampling events. PWSs shall return to screening and/or observation according to the current condition of the bloom. If treatment has been proven to be consistently effective at algal toxin removal, the Director may consider decreasing sampling frequency.

c. Sample Locations

(1) Raw water samples for algal toxin monitoring shall be collected from the raw water tap to characterize the quality of the water entering the treatment system.

(2) Finished water samples for algal toxin monitoring shall be collected at the entry point to the distribution system.

d. Algal toxin samples shall be collected and analyzed in accordance with § 1.21 of this Part.

5. Response to Algal Toxin MCL Exceedance

a. If any algal toxin exceeds the MCL listed in § 1.6.10(A) of this Part in any routine weekly samples collected at the finished water sampling point, the PWS shall:

(1) As soon as possible, but no later than twenty-four hours after receiving the results of the initial MCL exceedance, collect one resample from each raw water sampling point and one resample from each finished water sampling point. Analysis of resamples must be completed within twenty-four hours of collection.

(2) Within twenty-four hours of collecting the resamples, collect one repeat sample from each finished water sampling point. Analysis of repeat samples must be completed within twenty-four hours of collection.

(3) If any algal toxin concentration exceeds the MCL in any resample or repeat sample collected at a finished water sampling point, as soon as practical but no more than three hours after receiving the sample results, the surface water PWS shall notify all consecutive PWSs of the MCL exceedance. The surface water PWS, within twenty-four hours of receiving the sample results, shall collect samples at each routine coliform sampling site as identified under § 1.16.4 of this Part. Additional distribution system monitoring may be required by the Director based on sampling results and other relevant circumstances. Analysis of distribution samples must be completed within twenty-four hours of collection.

b. Consecutive PWS receiving water from a surface water PWS.

(1) Within twenty-four hours of receiving notification of an MCL exceedance in accordance with § 1.6.10(A) of this Part, the consecutive PWS shall collect samples at each routine coliform sampling site as identified in § 1.16.4 of this Part.

(2) Additional distribution system monitoring may be required by the Director based on sampling results and other relevant circumstances.

(3) Analysis of distribution samples must be completed within twenty-four hours of collection.

c. Revised cyanobacteria screening or algal toxin monitoring frequency.

(1) The cyanobacteria screening or algal toxin monitoring frequency may be revised at the discretion of the Director.

(2) When establishing the revised schedule, the Director may consider cyanobacteria screening data collected in accordance with this Part, algal toxin data, and other information provided by the PWS, including data from other screening tools (such as phycocyanin sensors or phytoplankton enumeration) and treatment information.

(3) Surface water PWSs shall monitor in accordance with the revised cyanobacteria screening or revised routine algal toxin monitoring schedule established by the Director.

d. Monitoring extension

(1) Upon a request from a PWS, the Director may agree to extend the twenty-four-hour monitoring requirement for resample, repeat or distribution samples required pursuant to this Part on a case-by-case basis when the PWS has a logistical problem collecting samples within twenty-four hours or with analyzing samples in accordance with the requirements of this Part.

(2) When an extension is agreed to by the Director, the Director shall specify in writing how much time the PWS has to monitor.

(3) Examples of potential logistical problems include, but are not limited to:

(AA) Extreme weather conditions create unsafe travel or on-site conditions for the person collecting the sample.

(BB) Limited certified laboratory capacity on weekends and holidays.

6. Harmful Algal Blooms - Treatment

a. This rule applies to all PWSs except consecutive PWS.

b. All § 1.6 PWS shall develop and submit to the Director written treatment optimization protocols. The protocols shall include treatment adjustments that will be made under various raw and finished water conditions. In developing the protocols, the PWS shall review and optimize existing treatment for algal toxins, considering effective strategies for algal toxin treatment such as:

(1) Avoiding lysing cyanobacterial cells;

(2) Optimizing removal of intact cells;

(3) Optimizing barriers for extracellular algal toxin removal or destruction;

(4) Optimizing sludge removal; and

(5) Discontinuing or minimizing backwash recycling.

c. The treatment optimization protocols shall be submitted to the Director in accordance with the following timelines:

(1) Within thirty days of the effective date of this rule, for PWSs which have detected algal toxins in a sample collected prior to the effective date of this rule.

(2) Within one year of the effective date of this rule, for PWSs which have not detected algal toxins in a sample collected prior to the effective date of this rule, or within thirty days of a detected algal toxin, whichever comes first.

d. A PWS shall comply with all of the following when monitoring conducted in accordance with this Section indicates algal toxin concentrations exceed the MCL in a sample collected at the raw water sampling point more than once within a consecutive twelve-month period, or when algal toxins are detected in a sample collected at a finished water sampling point or a distribution sampling point:

(1) Within one hundred and twenty days, the PWS shall submit an algal toxin general plan to the Director for approval. The algal toxin general plan shall include both short-term and long-term actions to prevent exceedances of the algal toxin MCLs established in § 1.6.10(A) of this Part in finished water. The algal toxin general plan shall include a schedule for implementation or a demonstration that existing practices are sufficient to prevent exceedances of the algal toxin MCLs in finished water.

(2) Implement the approved algal toxin general plan in accordance with the approved schedule.

e. Continue to monitor for algal toxins in accordance with §§ 1.6.10(B), (C) and (D) of this Part to demonstrate treatment effectiveness.

f. Failure to comply with screening and toxin monitoring requirements in §§ 1.6.10(D)(3) and (4) of this Part is a monitoring violation and requires the PWS to provide Tier 2 public notification in accordance with § 1.16.6 of this Part. Failure to comply with resample and repeat sample requirements in § 1.6.10(D)(5)(a) of this Part is a monitoring violation and requires the PWS to provide a Tier 1 public notification in accordance with § 1.16.6 of this Part.

g. If the PWS does not comply with §§ 1.6.10(D)(5)(b) through 1.6.10(D)(5)(d) of this Part, the PWS is in violation of the treatment technique requirements of this Part and shall issue Tier 2 public notification in accordance with § 1.16.6 of this Part using the standard health effects language in § 1.16.8 of this Part.

7. Public Notification and Data Reporting

a. The failure to complete any screening or monitoring requirement, the presence of a severe bloom in a source being used for water supply, all raw water screening for cyanobacteria, and monitoring results for algal toxins shall be reported to the Director within the first ten days following the month in which the bloom occurred, or the results were received. Any finished water monitoring result in which algal toxin is detected shall be reported no later than the next business day following the day that the PWS learns of the detection.

b. A PWS which has exceeded the MCL for an algal toxin in finished water must notify the public in accordance with § 1.16.6 of this Part Tier 1 public noticing requirements and as indicated below, using the standard health effects language of § 1.16.8 of this Part.

Tier 1 Public Notice Use Restrictions	Microcystin µg/L	Anatoxin-a µg/L	Cylindro- spermopsin µg/L	Saxitoxin µg/L
DO NOT DRINK WARNING	0.3-20	20-300	1-20	0.2-3
DO NOT USE WARNING	>20	>300	>20	>3

c. The use restrictions may be modified when toxin levels for two consecutive samples collected at least twenty-four hours apart indicate modification would be appropriate. This change will require additional public notification.

d. The PWS may end the issuance of public notification when the algal toxin levels in finished water are below the MCL in two consecutive samples collected a minimum of twenty-four hours apart.

e. A PWS that fails to screen for cyanobacteria or monitor for algal toxins in accordance with the requirements of § 1.6.10 of this Part must notify the public in accordance with § 1.16.6 of this Part.

216 R.I. Code R. 216-RICR-50-05-1.6

Amended effective 9/18/2024