16 Del. Admin. Code § 4462-9.0

Current through Register Vol. 28, No. 7, January 1, 2025

Section 4462-9.0 - Inorganic and Organic Chemical Requirements

9.1 Inorganic Chemical Requirements

9.1.1 PMCLs AND SMCLs: The following are the inorganic PMCLs and SMCLs (mg/L - milligrams per liter). Compliance is determined pursuant to subsection 9.1.2 through 9.1.13.

9.1.1.1 Table of PMCLs

PMCLs Substance	MCL
Antimony (Sb)	0.006 mg/L
Arsenic (As)	0.010 mg/L
Asbestos	7 MF/L*
Barium (Ba)	2 mg/L
Beryllium (Be)	0.004 mg/L
Cadmium (Cd)	0.005 mg/L
Chromium (Cr)	0.1 mg/L
Cyanide (Cn)	0.2 mg/L
Fluoride (F)	2.0 mg/L (See subsections 9.1.8 and 9.1.14)
Mercury (Hg)	0.002 mg/L
Nickel (Ni)	0.1 mg/L
Nitrate-Nitrogen (NO3-N)	10 mg/L (See subsections 9.1.6 and 9.1.8)
Nitrite-Nitrogen (NO2-N)	1 mg/L (See subsections 9.1.7 and 9.1.8)
Total Nitrate-Nitrogen and Nitrite-Nitrogen (NO3-N + NO2-N)	10 mg/L
Selenium (Se)	0.05 mg/L
Thallium (Tl)	0.002 mg/L
Turbidity	See subsection 7.1

*MFL - million fibers per liter, with fiber length > 10 microns

9.1.1.2 Table of SMCLs

SMCLs Substance	MCL
Aluminum	0.05-0.2 mg/L
Chloride (Cl)	250 mg/L
Color	15 color units
Corrosivity	Noncorrosive (See Section 11.0)
Foaming agents	0.50 mg/L
Iron (Fe)	0.30 mg/L
Manganese (Mn)	0.05 mg/L
Odor	3 threshold odor number
pH	6.5-8.5
Silver	0.1 mg/L
Sulfate (SO4)	250 mg/L
Total Dissolved Solids (TDS)	500 mg/L
Zinc (Zn)	5 mg/L

9.1.1.3 Table for Lead/Copper MCLGs: The Maximum Contaminant Level Goals (MCLG) for lead and copper are as follows:

Lead	0 mg/L
Copper	1.3 mg/L

9.1.2 Sampling and Analytical Requirements:

9.1.2.1 Community water systems shall conduct monitoring to determine compliance with the maximum contaminant levels specified in subsection 9.1.1 in accordance with subsections 9.1.3 through 9.1.13. Non-transient, non-community water systems shall conduct monitoring to determine compliance with the maximum contaminant levels specified in subsection 9.1.1 in accordance with subsections 9.1.3 through 9.1.13. Transient, non-community water systems shall conduct monitoring to determine compliance with the nitrate and nitrite maximum contaminant levels in subsection 9.1.1 in accordance with subsections 9.1.3 through 9.1.13.

9.1.2.2 Detection limits for each analytical method shall be in accordance with 40 CFR 141.23(a)(4)(i) as amended. Copies may be obtained from the Office of Drinking Water.

9.1.3 Monitoring shall be conducted as follows:

9.1.3.1 Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment [hereafter called a sampling point] beginning in the compliance period starting January 1, 1993. The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.

9.1.3.1.1 Groundwater systems with 150 or more service connections shall begin monitoring for Phase II and Phase V contaminants on January 1, 1993.

9.1.3.1.2 Groundwater systems with less than 150 service connections shall begin monitoring for Phase II contaminants on January 1, 1993 and for Phase V contaminants on January 1, 1996.

9.1.3.2 Surface water systems shall take a minimum of one sample at every entry point to the distribution system after any application of treatment or in the distribution system at a point which is representative of each source after treatment [hereafter called a sampling point] beginning in the compliance period beginning January 1, 1993. The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.

NOTE: For purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.

9.1.3.2.1 Surface water systems with 150 or more service connections shall begin monitoring for Phase II and Phase V contaminants on January 1, 1993.

9.1.3.2.2 Surface water systems with less than 150 service connections shall begin monitoring for Phase II contaminants on January 1, 1993 and for Phase V contaminants on January 1, 1996.

9.1.3.3 If a system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water is representative of all sources being used).

9.1.3.4 The Division may reduce the total number of samples which must be analyzed by allowing the use of compositing. Composite samples from a maximum of five sampling points are allowed provided that the detection limit of the method used for analysis is less than one-fifth of the MCL. Compositing of samples must be done in the laboratory.

9.1.3.4.1 If the concentration in the composite sample is greater than or equal to one-fifth of the MCL of any inorganic chemical, then a follow-up sample must be taken within 14 days at each sampling point included in the composite. These samples must be analyzed for the contaminants which exceeded one-fifth of the MCL in the composite sample.

9.1.3.4.2 If the population served by the system is >3,300 persons, then compositing may only be permitted by the Division at sampling points within a single system. In systems serving [LESS THEN OR EQUAL TO]3,300 persons, the Division may permit compositing among different systems provided the 5-sample limit is maintained.

9.1.3.4.3 If duplicates of the original sample taken from each sampling point used in the composite are available, the system may use these instead of resampling. The duplicates must be analyzed and the results reported to the Division within 14 days of collection

9.1.3.5 The frequency of monitoring for asbestos shall be in accordance with subsection 9.1.4; the frequency of monitoring for antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium and thallium shall be in accordance with subsection 9.1.5; the frequency of monitoring for nitrate shall be in accordance with subsection 9.1.6; and the frequency of monitoring for nitrite shall be in accordance with subsection 9.1.7.

9.1.4 The frequency of monitoring conducted to determine compliance with the maximum contaminant level for asbestos specified in subsection 9.1.1 shall be conducted as follows:

9.1.4.1 Each community and non-transient, non-community water system is required to monitor for asbestos during the first three-year compliance period of each nine-year compliance cycle beginning in the compliance period starting January 1, 1993.

9.1.4.2 If the system believes it is not vulnerable to either asbestos contamination in its source water or due to corrosion of asbestos-cement pipe, or both, it may apply to the Division for a waiver of the monitoring requirement in subsection 9.1.4.1. If the Division grants the waiver, the system is not required to monitor.

9.1.4.3 The Division may grant a waiver based on a consideration of the following factors:

9.1.4.3.1 Potential asbestos contamination of the water source, and

9.1.4.3.2 The use of asbestos-cement pipe for finished water distribution and the corrosive nature of the water.

9.1.4.4 A waiver remains in effect until the completion of the three-year compliance period. Systems not receiving a waiver must monitor in accordance with the provisions of subsection 9.1 .4.1.

9.1.4.5 A system vulnerable to asbestos contamination due solely to corrosion of asbestos-cement pipe shall take one sample at a tap served by asbestos-cement pipe and under conditions where asbestos contamination is most likely to occur.

9.1.4.6 A system vulnerable to asbestos contamination due solely to source water shall monitor in accordance with the provision of subsection 9.1.3.

9.1.4.7 A system vulnerable to asbestos contamination due both to its source water supply and corrosion of asbestos-cement pipe shall take one sample at each entry point after treatment and a minimum of one tap sample served by asbestos-cement pipe and under conditions where asbestos contamination is most likely to occur.

9.1.4.8 A system which exceeds PMCL listed in subsection 9.1.1 shall monitor quarterly beginning in the next quarter after the violation occurred.

9.1.4.9 The Division may decrease the quarterly monitoring requirement to the frequency specified in subsection 9.1.4.1 provided the Division has determined that the system is reliably and consistently below the maximum contaminant level. In no case can a Division make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface (or combined surface/ground) water system takes a minimum of four quarterly samples.

9.1.4.10 If monitoring data collected after January 1, 1990 are generally consistent with the requirements of this section then the Division may allow systems to use that data to satisfy the monitoring requirement for the initial compliance period beginning January 1, 1993.

9.1.5 The frequency of monitoring conducted to determine compliance with the maximum contaminant levels in subsection 9.1.1 for antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium and thallium shall be as follows:

9.1.5.1 Groundwater systems shall take one sample at each sampling point once every three (3) years. Surface Water systems [or combined surface/ground] shall take one sample annually at each sampling point beginning January 1, 1993.

9.1.5.2 The system may apply to the Division for a waiver from the monitoring frequencies specified in subsection 9.1 .5.1.

9.1.5.3 A condition of the waiver shall require that a system shall take a minimum of one sample while the waiver is effective. The term during which the waiver is effective shall not exceed one compliance cycle (i.e., nine years).

9.1.5.4 The Division may grant a waiver provided surface water systems have monitored annually for at least three years and groundwater systems have conducted a minimum of three rounds of monitoring. (At least one sample shall have been taken since January 1, 1990.) Both surface and groundwater systems shall demonstrate that all previous analytical results were less than the maximum contaminant level. Systems that use a new water source are not eligible for a waiver until three rounds of monitoring from the new source have been completed.

9.1.5.5 In determining the appropriate reduced monitoring frequency, the Division shall consider:

9.1.5.5.1 Reported concentrations from all previous monitoring;

9.1.5.5.2 The degree of variation in reported concentrations; and

9.1.5.5.3 Other factors which may affect contaminant concentrations such as changes in groundwater pumping rates, changes in the systems configuration, changes in the system's operating procedures, or changes in stream flows or characteristics.

9.1.5.6 A decision by the Division to grant a waiver shall be made in writing and shall set forth the basis for the determination. The determination may be initiated by the Division or upon an application by the public water system. The public water system shall specify the basis for its request. The Division shall review and, where appropriate, revise its determination of the appropriate monitoring frequency when the system submits new monitoring data or when other data relevant to the system's appropriate monitoring frequency become available.

9.1.5.7 Systems which exceed the MCLs as calculated in subsection 9.1.11 shall monitor quarterly beginning in the next quarter after the violation occurred.

9.1.5.8 The Division may decrease the quarterly monitoring requirement to the frequencies specified in subsections 9.1.5.1 and 9.1.5.2 provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case can the Division make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples.

9.1.5.9 All new systems that use a new source of water or existing systems that add a new source of water that begin operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the Division. The system must also comply with the initial sampling frequencies specified by the Division to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in this section.

9.1.6 All public water systems (community; non-transient, non-community; and transient, non-community systems) shall monitor to determine compliance with the maximum contaminant level for nitrate in subsection 9.1.1.

9.1.6.1 Community and non-transient, non-community water systems served by groundwater systems shall monitor annually and systems served by surface water shall monitor quarterly.

9.1.6.2 For community and non-transient, non-community water systems, the repeat monitoring frequency for groundwater systems shall be quarterly for at least one year following any one sample in which the concentration is [GREATER THEN OR EQUAL TO]50 percent of the MCL. The Division may allow a groundwater system to reduce the sampling frequency to annually after four consecutive quarterly samples are reliably and consistently less than 85 percent of the MCL.

9.1.6.3 For community and non-transient, non-community water systems, the Division may allow a surface water system to reduce the sampling frequency to annually if all analytical results from four consecutive quarters are <50 percent of the MCL. A surface water system shall return to quarterly monitoring if any one sample is [GREATER THEN OR EQUAL TO]50 percent of the MCL.

9.1.6.4 Each transient non-community water system shall monitor annually beginning January 1, 1993.

9.1.6.5 After the initial round of quarterly sampling is completed, each community and non-transient non-community system which is monitoring annually shall take subsequent samples during the quarter(s) which previously resulted in the highest analytical result.

9.1.7 All public water systems (community; non-transient, non-community; and transient, non-community systems) shall monitor to determine compliance with the maximum contaminant level for nitrite in subsection 9.1.1

9.1.7.1 All public water systems shall take one sample at each sampling point in the distribution system during the compliance period beginning January 1, 1993 and ending December 31, 1995.

9.1.7.2 After the initial sample, systems where an analytical result for nitrite is <50 percent of the MCL shall monitor at the frequency specified by the Division.

9.1.7.3 For community, non-transient, non-community, and transient non-community water systems, the repeat monitoring frequency for any water system shall be quarterly for at least one year following any one sample in which the concentration is [GREATER THEN OR EQUAL TO]50 percent of the MCL. The Division may allow a system to reduce the sampling frequency to annually after determining the system is reliably and consistently less than the MCL.

9.1.7.4 Systems which are monitoring annually shall take each subsequent sample during the quarter(s) which previously resulted in the highest analytical result.

9.1.8 Confirmation Samples:

9.1.8.1 Where the results of sampling for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium, or thallium indicate an exceedance of the maximum contaminant level, the Division may require that one additional sample be collected, as soon as possible after the initial sample was taken (but not to exceed two weeks), at the same sampling point.

9.1.8.2 Where nitrate or nitrite sampling results indicate an exceedance of the maximum contaminant level, the system shall take a confirmation sample within 24 hours of the system's receipt of notification of the analytical results of the first sample. Systems unable to comply with the 24-hour sampling requirement must immediately notify the consumers in the area served by the public water system in accordance with subsection 4.2. Systems exercising this option must take and analyze a confirmation sample within two weeks of notification of the analytical results of the first sample.

9.1.8.3 If a Division-required confirmation sample is taken for any contaminant, then the results of the initial and confirmation sample shall be averaged. The resulting average shall be used to determine the system's compliance in accordance with subsection 9.1.11. The Division has the discretion to delete results of obvious sampling errors. Sampling errors include, but are not limited to samples collected from the wrong system or samples collected from private wells located within a public water system.

9.1.9 The Division may require more frequent monitoring than specified in subsections 9.1.4, 9.1.5, 9.1.6 and 9.1.7 or may require confirmation samples for positive and negative results at its discretion.

9.1.10 Systems may apply to the Division to conduct more frequent monitoring than the minimum monitoring frequencies specified in this section.

9.1.11 Compliance with subsection 9.1.1 shall be determined based on the analytical result(s) obtained at each sampling point:

9.1.11.1 For systems which are conducting monitoring at a frequency greater than annual, compliance with the maximum contaminant levels for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium, and thallium is determined by a running annual average at each sampling point. If the average at any sampling point is greater than the MCL, then the system is out of compliance. If any one sample would cause the annual average to be exceeded, then the system is out of compliance immediately. Any sample below the detection limit shall be calculated at zero for the purpose of determining the annual average. If a system fails to collect the required number of samples, compliance (average concentration) will be based on the total number of samples collected.

9.1.11.2 For systems which are monitoring annually, or less frequently, the system is out of compliance with the maximum contaminant levels for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium, and thallium if the level of a contaminant at any sampling point is greater than the MCL. If a confirmation sample is required by the Division, the determination of compliance will be based on the annual average of the initial MCL exceedance and any Division-required confirmation samples. If a system fails to collect the required number of samples, compliance (average concentration) will be based on the total number of samples collected.

9.1.11.3 Compliance with the maximum contaminant levels for nitrate and nitrite is determined based on one sample if the levels of these contaminants are below the MCLs. If the levels of nitrate and/or nitrite exceed the MCLs in the initial sample, a confirmation sample is required and compliance shall be determined based on the average of the initial and confirmation samples.

9.1.11.4 If a public water system has a distribution system separable from other parts of the distribution system with no interconnections, the Division may allow the system to give public notice to only the area served by that portion of the system which is out of compliance.

9.1.11.5 Arsenic sampling results will be reported to the nearest 0.001 mg/L.

9.1.12 Each public water system shall monitor at the time designated by the Division during each compliance period.

9.1.13 At the discretion of the Division, nitrate levels not to exceed 20 mg/L may be allowed in TNCWS and NTNCWS if the supplier of water demonstrates to the satisfaction of the Division that:

9.1.13.1 Such water will not be available to children under one (1) year of age;

9.1.13.2 There will be continuous posting of the fact that nitrate levels exceed ten (10) mg/L and the potential health effects of exposure and;

9.1.13.3 No adverse health effects shall result.

9.1.14 Fluoride (F):

9.1.14.1 Where fluoridation has been or will be instituted as required under 16 Del.C. § 124, the target level for fluoride shall be 0.7 mg/L. An operational control range shall be maintained so that monthly average fluoride levels and 80% of daily fluoride measurements are between 0.6 mg/L and 1.0 mg/L. Fluoride levels shall not exceed 2.0 mg/L. Defluoridation of water shall be provided when the natural fluoride concentration exceeds 2.0 mg/L. In addition to the sampling and analysis required by subsection 9.1.5, fluoridated and defluoridated water supplies shall be sampled and analyzed daily by the supplier of water at a representative point(s) in the water supply system. In the event that the fluoride level exceeds 2.0 mg/L, samples shall be taken every two hours until the level returns to 2.0 mg/L or less. The exceedance shall be treated as a Tier 2 violation requiring public notification. If the fluoride level exceeds 4.0 mg/L a Tier 1 public notice is required. The fluoride levels shall be reported to the Division pursuant to subsection 4.1.1.

9.1.14.2 All municipal water supplies, whether municipally owned or privately owned, shall comply with subsection 9.1.14.1. All affected water supplies shall submit cost estimates to the Department of Health and Social Services no later than November 15, 1998.

9.1.15 Sodium (Na):

9.1.15.1 The supplier of water for a CWS shall collect and analyze one (1) sample per plant at the entry point of the distribution system for the determination of sodium concentration levels; samples must be collected and analyzed annually for systems utilizing surface water sources in whole or in part and at least every three (3) years for systems utilizing solely ground water sources. The minimum number of samples required to be taken by the system shall be based on the number of treatment plants used by the system, except that multiple wells drawing raw water from a single aquifer may, with Division approval be considered one (1) treatment plant for determining the minimum number of samples. The supplier of water may be required by the Division to collect and analyze water samples for sodium more frequently in locations where the sodium content is variable.

9.1.15.2 The supplier of water shall report to the Division the results of analyses for sodium pursuant to subsection 4.1.1.

9.1.15.3 The supplier of water shall notify appropriate local and State public health officials of the sodium levels by written notice by direct mail within three (3) months. A copy of each notice required to be provided by this paragraph shall be sent to the Division within ten (10) days of issuance. The supplier of water is not required to notify appropriate local public health officials of the sodium levels where the Division provides such notices in lieu of the supplier.

9.1.15.4 Analysis for sodium shall be performed in accordance with 40 CFR 141.23(k)(1) as amended. Copies may be obtained from the Office of Drinking Water.

9.1.16 Inorganic Compliance Determination:

9.1.16.1 Analysis for the purpose of determining compliance with subsection 9.1.1 shall be in accordance with the following:

9.1.16.1.1 PMCL analyses for all CWSs utilizing surface water sources shall be conducted annually. SMCL analyses shall be performed at the discretion of the Division.

9.1.16.1.2 PMCL analyses for all CWSs utilizing only ground water sources shall be conducted at three (3) year intervals. SMCL analyses shall be performed at the discretion of the Division.

9.1.16.1.3 For TNCWSs and NTNCWSs, whether supplied by surface or ground water sources, analyses for the purpose of determining compliance for nitrate shall be conducted at intervals determined by the Division.

9.1.16.1.4 The Division has the authority to determine compliance or initiate enforcement action based upon analytical results and other information compiled by its sanctioned representatives and agencies.

9.1.16.2 The provision of subsections 9.1.6 and 9.1.7 notwithstanding compliance with the PMCL for nitrate shall be determined on the basis of the mean of two (2) analyses. When a level exceeding the PMCL for nitrate is found, a second analysis shall be initiated within twenty-four (24) hours, and if the mean of the two (2) analyses exceeds the PMCL, the supplier of water shall report his findings to the Division pursuant to subsection 4.1 and shall notify the public pursuant to subsection 4.2.

9.1.16.3 For the initial analyses required by subsections 9.1.16.1, 9.1.16.2 and 9.1.16.3, data for surface waters acquired within one (1) year prior to the effective date and data for ground waters acquired within three (3) years prior to the effective date of this section may be substituted at the discretion of the Division.

9.1.17 Analytical Methodology:

9.1.17.1 Analyses conducted to determine compliance with subsection 9.1.1 for inorganic chemicals shall be made in accordance with the following methods.

9.1.17.1.1 PMCLs shall be in accordance with 40 CFR 141.23(k)(1) as amended. Copies may be obtained from the Office of Drinking Water.

9.1.17.1.2 SMCLs shall be accordance with 40 CFR section 143.4 as amended. Copies may be obtained from the Office of Drinking Water.

9.1.17.1.3 Sample Collection and Preservation: - Sample collection for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, nitrate, nitrite, selenium and thallium under this section shall be conducted using the sample preservation method(s), container, and maximum holding time procedures in accordance with 40 CFR 141.23(k)(2) as amended. Copies may be obtained from the Office of Drinking Water.

9.1.17.1.4 Lab Approval: Analysis under this section shall only be conducted by laboratories that have received approval by EPA, other approved certifying organization, or the State of Delaware. To receive approval to conduct analyses for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, nitrate, nitrite, selenium and thallium the laboratory must:

9.1.17.1.4.1 Analyze Performance Evaluation samples annually in accordance with subsection 1.14; and

9.1.17.1.4.2 Achieve quantitative results on the analyses that are in accordance with 40 CFR 141.23(k)(3)(ii) as amended. Copies may be obtained from the Office of Drinking Water.

9.2 Organic Chemical Requirements:

9.2.1 PMCLs: The following are the organic PMCLs (mg/L-milligrams per liter). Compliance is determined pursuant to subsections 9.2.2, 9.2.3, and 9.2.4.

9.2.1.1 The following maximum contaminant levels for synthetic organic contaminants apply to community water systems and non-transient, non-community water systems:

Pesticides and PCBs

Contaminant	MCL
Alachlor	0.002 mg/L
Atrazine	0.003 mg/L
Benzo(a)pyrene	0.0002 m g/L
Carbofuran	0.04 mg/L
Chlordane	0.002 mg/L
Dalapon	0.2 mg/L
Di(2-ethylhexyl) adipate	0.4 mg/L
Di(2-ethylhexyl) phthalate	0.006 mg/L
Dibromochloropropane	0.0002 mg/L
Dinoseb	0.007 mg/L
Diquat	0.02 mg/L
2,4-D	0.07 mg/L
Endothall	0.1 mg/L
Endrin	0.002 mg/L
Ethylenedibromide (EDB)	0.00005 mg/L
Glyphosate	0.7 mg/L
Heptachlor	0.0004 mg/L
Heptachlor epoxide	0.0002 mg/L
Hexachlorobenzene	0.001 mg/L
Hexachlorocyclopentadiene	0.05 mg/L
Lindane	0.0002 mg/L
Methoxychlor	0.04 mg/L
Oxamyl (Vydate)	0.2 mg/L
Pentachlorophenol	0.001 mg/L
Picloram	0.5 mg/L
Polychlorinated biphenyls (PCBs)	0.0005 mg/L
Simazine	0.004 mg/L
2,3,7,8-TCDD (Dioxin)	3 X 10-8 mg/L
Toxaphene	0.003 mg/L
2,4,5-TP (Silvex)	0.05 mg/L

9.2.1.2 Disinfection Byproducts (DBPs)

Contaminant	MCL
Total Trihalomethanes (TTHMs)	0.080 mg/L
Haloacetic acids (five) (HAA5)	0.060 mg/L
Bromate	0.010 mg/L
Chlorite	1.0 mg/L

9.2.1.2.1 Maximum Contaminant Level Goals for disinfection byproducts.

Disinfection byproduct	MCLG mg/L
Bromodichloromethane	Zero
Bromoform	Zero
Bromate	Zero
Chlorite	0.8
Chloroform	0.07
Dibromochloromethane	0.06
Dichloroacetic acid	Zero
Monochloroacetic acid	0.07
Trichloroacetic acid	0.02

9.2.1.3 Volatile Synthetic Organic Chemicals (VOCs)

Contaminant	MCL
Benzene	0.005 mg/L
Carbon Tetrachloride	0.005 mg/L
1,2-Dichlorobenzene	0.6 mg/L
1,4-Dichlorobenzene	0.075 mg/ L
1,2 Dichloroethane	0.005 mg/L
1,1 Dichloroethylene	0.007 mg/L
Cis-1,2-Dichloroethylene	0.07 mg/L
Trans 1,2 Dichloroethylene	0.1 mg/L
Dichloromethane	0.005 mg/L
1,2 Dichloropropane	0.005 mg/L
Ethylbenzene	0.7 mg/L
Methyl tert Butyl Ether (MTBE)	0.01 mg/L
Monochlorobenzene	0.1 mg/L
Styrene	0.1 mg/L
Tetrachloroethylene1,2,3	0.001 mg/L
Toluene	1 mg/L
1,2,4-Trichlorobenzene	0.07 mg/L
1,1,1-Trichloroethane	0.2 mg/L
1,1,2-Trichloroethane	0.005 mg/L
Trichloroethylene1,2,3	0.001 mg/L
Vinyl Chloride1,2,3	0.001 mg/L
Xylenes (total)	10 mg/L

¹ The MCL for these compounds will be lowered to 0.001 mg/L effective January 1, 2013.

² Systems that meet the federal MCL of 0.005 mg/L on January 1, 2013 effective date yet do not comply with the 0.001 mg/L shall have until January 1, 2015 to reach compliance.

³ For enforcement purposes during the transition period from January 1, 2013 until January 1, 2015 any water system not meeting the MCL of 0.001 mg/L on January 1, 2013, shall continue to be monitored for enforcement purposes at the federal MCL of 0.005 mg/L until January 1, 2015. On January 1, 2015 the state MCL of 0.001 mg/L goes into full effect.

9.2.2 Sampling, Analytical Requirements and Compliance Determination for Contaminants Listed in subsections 9.2.1.1, 9.2.1.2 and 9.2.1.3:

9.2.2.1 Monitoring of the contaminants listed in subsection 9.2.1.1 for the purposes of determining compliance with the MCLs shall be conducted as follows:

9.2.2.1.1 Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.

9.2.2.1.2 Surface water systems shall take a minimum of one sample at points in the distribution system that are representative of each source or at each entry point to the distribution system after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant. (NOTE: For purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources).

9.2.2.1.3 If the system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating condition (i.e., when water representative of all sources is being used).

9.2.2.1.4 Monitoring frequency:

9.2.2.1.4.1 Each community and non-transient non-community water system shall take four consecutive quarterly samples for each contaminant listed in subsection 9.2.1.1 during each compliance period beginning with the compliance period starting January 1, 1993.

9.2.2.1.4.2 Systems serving more than 3,300 persons which do not detect a contaminant in the initial compliance period may reduce the sampling frequency to a minimum of two quarterly samples in one year during each repeat compliance period.

9.2.2.1.4.3 Systems serving less than or equal to 3,300 persons which do not detect a contaminant in the initial compliance period may reduce the sampling frequency to a minimum of one sample during each repeat compliance period.

9.2.2.1.5 Each community and non-transient water system which does not detect a contaminant listed in subsection 9.2.1.1 may apply to the Division for a waiver from the requirement of subsection 9.2 .2.1.4.1 upon completion of the initial monitoring. A system must reapply for a waiver at the end of each compliance period.

9.2.2.1.6 The Division may grant a waiver after evaluating the following factors: Knowledge of previous use (including transport, storage, or disposal) of the contaminant within the watershed or zone of influence of the system. If a determination by the Division reveals no previous use of the contaminant within the watershed or zone of influence, a waiver may be granted. If previous use of the contaminant is unknown, or it has been used previously, then the following factors shall be used to determine whether a waiver is granted:

9.2.2.1.6.1 Previous analytical results.

9.2.2.1.6.2 The proximity of the system to a potential point or non-point source of contamination. Point sources include spills and leaks of chemicals at or near water treatment facilities or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities. Non-point sources include the use of pesticides to control insect and weed pests on agricultural areas, forest lands, home and gardens, and other land application uses.

9.2.2.1.6.3 The environmental persistence and transport of the pesticide or PCBs.

9.2.2.1.6.4 How well the water source is protected against contamination due to such factors as depth of the well, the type of soil and the integrity of the well casing.

9.2.2.1.6.5 Elevated nitrate levels at the water supply source.

9.2.2.1.6.6 Use of PCBs in equipment used in the production, storage or distribution of water (i.e., PCBs used in pumps, transformers, etc.).

9.2.2.1.7 If an organic contaminant listed in subsection 9.2.1.1 is detected in any sample then:

9.2.2.1.7.1 Each system must monitor quarterly at each sampling point which resulted in a detection.

9.2.2.1.7.2 The Division may decrease the quarterly monitoring requirement specified in subsection 9.2.2.7.1 provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case shall the Division make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system take a minimum of four quarterly samples.

9.2.2.1.7.3 After the Division determines the system is reliably and consistently below the maximum contaminant level the Division may allow the system to monitor annually. Systems which monitor annually must monitor during the quarter that previously yielded the highest analytical result.

9.2.2.1.7.4 Systems which have 3 consecutive annual samples with no detection of a contaminant may apply to the Division for a waiver as specified in subsection 9.2.2.1.6; and

9.2.2.1.7.5 If monitoring results in detection of one or more of certain related contaminants (heptachlor or heptachlor epoxide), then subsequent monitoring shall analyze for all related contaminants.

9.2.2.1.8 Systems which violate the MCL listed in subsection 9.2.1.1 must monitor quarterly. After a minimum of four quarterly samples show the system is in compliance and the Division determines the system to be reliably and consistently below the MCL as specified in subsection 9.2.2.1.11, the system shall monitor at the frequency specified in subsection 9.2.2.1.7.3.

9.2.2.1.9 The Division may require a confirmation sample for positive or negative results. If a confirmation sample is required by the Division, the result must be averaged with the first sampling result and the average used for the compliance determination as specified in subsection 9.2.2.1.11. The Division has the discretion to delete results of obvious sampling errors from this calculation.

9.2.2.1.10 The Division may reduce the total number of samples a system must analyze by allowing the use of compositing. Composite samples from a maximum of five sampling points are allowed. Detection Limit must be less than one-fifth of the MCL. Compositing of samples must be done in the laboratory and analyzed within 14 days of sample collections.

9.2.2.1.10.1 If the concentration in the composite sample detects one or more contaminants listed in subsection 9.2.1.1 then a follow-up sample must be taken and analyzed within 14 days from each sampling point included in the composite.

9.2.2.1.10.2 If duplicates of the original sample taken from each sampling point used in the composite are available, the system may use these duplicates instead of resampling. The duplicate must be analyzed and the results reported to the Division within 14 days of collection.

9.2.2.1.10.3 If the population served by the system is >3,300 persons, then compositing may only be permitted by the Division at sampling points within a single system. In systems serving [LESS THEN OR EQUAL TO]3,300 persons, the Division may permit compositing among different systems provided the 5-sample limit is maintained.

9.2.2.1.11 Compliance with subsection 9.2.1.1 shall be determined based on the analytical results obtained at each sampling point. If one sampling point is in violation of the MCL, the system is in violation of the MCL.

9.2.2.1.11.1 For systems which are conducting monitoring at a frequency greater than annually, compliance is determined by a running annual average of all samples taken at each sampling point. If the annual average of any sampling point is greater than the MCL, then the system is out of compliance. If the initial sample or a subsequent sample would cause the annual average to be exceeded, then the system is out of compliance immediately. Any samples below the detection limit shall be calculated as zero for purposes of determining the annual average.

9.2.2.1.11.2 If monitoring is conducted annually, or less frequently, the system is out of compliance if the level of a contaminant at any sampling point is greater than the MCL. If a confirmation sample is required by the Division, the determination of compliance will be based on the average of the two samples.

9.2.2.1.11.3 If any sample result will cause the running annual average to exceed the MCL at any sampling point, the system is out of compliance with the MCL immediately.

9.2.2.1.11.4 If a system fails to collect the required number of samples, compliance will be based on the total number of samples collected.

9.2.2.1.11.5 If a sample result is less than the detection limit, zero will be used to calculate the annual average.

9.2.2.1.11.6 If a public water system has a distribution system separable from other parts of the distribution system with no interconnections, the Division may allow the system to give public notice to only that portion of the system which is out of compliance.

9.2.2.1.12 Analysis for the contaminants listed in subsection 9.2.1.1 shall be conducted in accordance with 40 CFR 141.24(e). Copies may be obtained from the Office of Drinking Water.

9.2.2.1.13 Analysis for PCBs shall be conducted as follows:

9.2.2.1.13.1 Each system which monitors for PCBs shall analyze each sample in accordance with 40 CFR 141.24(h)(13)(i) (see subsection 9.2.2.13.2). Copies may be obtained from the Office of Drinking Water.

9.2.2.1.13.2 If PCBs (as one of seven Aroclors) are detected (as designated in this 40 CFR 141.24(h)(13)(ii)) in any sample analyzed using subsection 9.2.2.13.1, the system shall reanalyze the sample in accordance with 40 CFR 141.24(h)(13)(ii) to quantitate PCBs (as decachlorobiphenyl). Copies may be obtained from the Office of Drinking Water.

9.2.2.1.13.3 Compliance with the PCB MCL shall be determined based upon the quantitative results of analyses conducted in accordance with 40 CFR 141.24(h)(13)(iii). Copies may be obtained from the Office of Drinking Water.

9.2.2.1.14 If monitoring data collected after January 1, 1990, are generally consistent with the requirements of subsection 9.2.2, then the Division may allow systems to use that data to satisfy the monitoring requirement for the initial compliance period beginning January 1, 1993.

9.2.2.1.15 The Division may increase the required monitoring frequency, where necessary, to detect variations within the system (e.g., fluctuations in concentration due to seasonal use, changes in water source).

9.2.2.1.16 The Division has the authority to determine compliance or initiate enforcement action based upon analytical results and other information compiled by their sanctioned representatives and agencies.

9.2.2.1.17 Each public water system shall monitor at the time designated by the Division within each compliance period.

9.2.2.1.18 Detection as used in this paragraph shall be defined as found in 40 CFR 141.24(h)(18). Copies may be obtained from the Office of Drinking Water.

9.2.2.1.19 Analysis under this section shall only be conducted by laboratories that have received certification by EPA or the Division and have met the following conditions:

9.2.2.1.19.1 To receive certification to conduct analyses for the contaminants in subsections 9.2.1.1 and 9.2.1.3 the laboratory must:

9.2.2.1.19.1.1 Analyze Performance Evaluation samples annually in accordance with subsection 1.14; and

9.2.2.1.19.1.2 The laboratory shall achieve quantitative results on the analyses that are within the acceptance limits: specified in 40 CFR 141.24(h)(19)(i)(B). Copies may be obtained from the Office of Drinking Water.

9.2.2.1.20 All new systems or systems that use a new source of water that begins operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the Division. The system must also comply with the initial sampling frequencies specified by the Division to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted with the requirements in this section.

9.2.2.2 Sampling, Analytical Requirements and Compliance Determination for VOCs: Monitoring of the contaminants listed in subsection 9.2.1.3 for the purpose of determining compliance with the MCLs shall be conducted as follows:

9.2.2.2.1 Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a sampling point). If conditions warrant, the Division may designate additional sampling points within the distribution system or at the consumer's tap which more accurately determine consumer exposure. Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.

9.2.2.2.2 Surface water systems shall take a minimum of one sample at points in the distribution system that are representative of each source or at each entry point to the distribution system after treatment (hereafter called a sampling point). If conditions warrant, the Division may designate additional sampling points within the distribution system or at the consumer's tap which more accurately determines consumer exposure. Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source, treatment plant, or within the distribution system. NOTE: For purposes of this paragraph, surface water systems include systems with a combination of surface and ground surfaces.

9.2.2.2.3 If the system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water representative of all sources is being used).

9.2.2.2.4 Each community and non-transient non-community water system shall take four consecutive quarterly samples for each contaminant listed in subsection 9.2.1.3, during each compliance period beginning in the initial compliance period.

9.2.2.2.5 Groundwater and surface water systems which do not detect one of the contaminants listed in subsection 9.2 .1.3 after conducting the initial round of monitoring required in subsection 9.2.2.2.4 of this section may take one sample annually.

9.2.2.2.6 For groundwater and surface water systems, if the initial monitoring for contaminants listed in subsection 9.2 .1.3 as allowed in subsection 9.2.2.2.18 has been completed by December 31, 1992 and the system did not detect any contaminant listed in subsection 9.2 .1.3 then the system shall take one sample annually. After a minimum of three years of annual sampling, the Division may allow groundwater systems which have no previous detection of any contaminant listed in subsection 9.2.1.3 to take one sample during each compliance period.

9.2.2.2.7 Each community and non-transient non-community groundwater system which does not detect a contaminant listed in subsection 9.2.1.3 may apply to the Division for a waiver from the requirement of subsections 9.2.2.2.5 and 9.2.2.2.6 after completing the initial monitoring. (For the purposes of this section, detection is defined as >0.0005 mg/L). A waiver shall be effective for no more than six years (two compliance periods).

9.2.2.2.7.1 The Division may also issue waivers to small systems (those serving [LESS THEN OR EQUAL TO]3,300 persons) for the initial round of monitoring for 1,2,4-trichlorobenzene.

9.2.2.2.8 The Division may grant a waiver after evaluating the following factor(s):

9.2.2.2.8.1 Knowledge of previous use (including transport, storage, or disposal) of the contaminant within the watershed or zone of influence of the system. If a determination by the Division reveals no previous use of the contaminant within the watershed or zone of influence, a waiver may be granted.

9.2.2.2.8.2 If previous use of the contaminant is unknown or it has been used previously, then the following factors shall be used to determine whether a waiver is granted.

9.2.2.2.8.2.1 Previous analytical results.

9.2.2.2.8.2.2 The proximity of the system to potential point or non-point source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities.

9.2.2.2.8.2.3 The environmental persistence and transport of the contaminants.

9.2.2.2.8.2.4 The number of persons served by the public water system and the proximity of a smaller system to a larger system.

9.2.2.2.8.2.5 How well the water source is protected against contamination such as whether it is a surface or groundwater system. Groundwater systems must consider factors such as depth of the well, the type of soil, and well head protection. Surface water systems must consider watershed protection.

9.2.2.2.9 As a condition of the waiver a system must take one sample at each sampling point during the time the waiver is effective (i.e., one sample during two compliance periods or six years) and update its vulnerability assessment considering the factors listed in subsection 9.2.2.2.8. Based on this vulnerability assessment the Division must confirm that the system is non-vulnerable. If the Division does not make this reconfirmation within three years of the initial determination, then the waiver is invalidated and the system is required to sample annually as specified in subsection 9.2.2.2.5.

9.2.2.2.10 Each community and non-transient non-community surface water system which does not detect a contaminant listed is subsection 9.2.1.3 may apply to the Division for a waiver from the requirements of subsection 9.2.2.2.6 after completing the initial monitoring. Composite samples from a maximum of five sampling points are allowed, provided that the detection limit of the method used for analysis is less than one-fifth of the MCL. Systems meeting this criterion must be determined by the Division to be non-vulnerable based on a vulnerability assessment during each compliance period. Each system receiving a waiver shall sample at the frequency specified by the Division (if any).

9.2.2.2.11 If a contaminant listed in subsection 9.2.1.3, excluding vinyl chloride, is detected at a level exceeding 0.0005 mg/L in any sample then:

9.2.2.2.11.1 The system must monitor quarterly at each sampling point which resulted in a detection;

9.2.2.2.11.2 The Division may decrease the quarterly monitoring requirement specified in subsection 9.2.2.2.11.1 provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case shall the Division make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples;

9.2.2.2.11.3 If the Division determines that the system is reliably and consistently below the MCL, the Division may allow the system to monitor annually. Systems which monitor annually must monitor during the quarter or quarters which previously yielded the highest analytical result;

9.2.2.2.11.4 Systems which have three consecutive annual samples with no detection of a contaminant may apply to the Division for a waiver as specified in subsection 9.2.2.2.7; and

9.2.2.2.11.5 Groundwater systems which have detected one or more of the following two-carbon organic compounds: trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, trans-1,2-dichloroethylene, 1,1,1-trichloroethane, cis-1,2-dichloroethylene or 1,1-dichloroethylene shall monitor quarterly for vinyl chloride. A vinyl chloride sample shall be taken at each sampling point at which one or more of the two-carbon organic compounds was detected. If the results of the first analysis do not detect vinyl chloride, the Division may reduce the quarterly monitoring frequency of vinyl chloride monitoring to one sample during each compliance period. Surface water systems are required to monitor for vinyl chloride as specified by the Division.

9.2.2.2.12 Systems which violate the requirements of subsection 9.2.1.3 as determined by subsection 9.2.2.2.15 must monitor quarterly. After a minimum of four consecutive quarterly samples shows the system is in compliance as specified in subsection 9.2.2.2.15, and the Division determines that the system is reliably and consistently below the maximum contaminant level, the system may monitor at the frequency and time specified in subsection 9.2.2.2.11.3.

9.2.2.2.13 The Division may require a confirmation sample for positive or negative results. If a confirmation sample is required by the Division, the result must be averaged with the first sampling result and the average is used for the compliance determination as specified by subsection 9.2.2.2.15. The Division has the discretion to delete results of obvious sampling errors from this calculation.

9.2.2.2.14 The Division may reduce the total number of samples a system must analyze by allowing the use of compositing. Composite samples from a maximum of five sampling points are allowed, providing that the detection limit of the method used for analysis is less than one-fifth of the MCL. Compositing of samples must be done in the laboratory and analyzed within 14 days of sample collection.

9.2.2.2.14.1 If the concentration in the composite sample is >0.0005 mg/L for any contaminant listed in subsection 9.2.1.3, then a follow-up sample must be taken and analyzed within 14 days from each sampling point included in the composite.

9.2.2.2.14.2 If duplicates of the original sample taken from each sampling point used in the composite are available, the system may use these instead of resampling. The duplicate must be analyzed and the results reported to the Division within 14 days of collection.

9.2.2.2.14.3 If the population served by the system is >3,300 persons, then compositing may only be permitted by the Division at sampling points within a single system. In systems serving [LESS THEN OR EQUAL TO]3,300 persons, the Division may permit compositing among different systems provided the 5-sample limit is maintained.

9.2.2.2.14.4 Compositing samples prior to GC analysis:

9.2.2.2.14.4.1 Add 5 ml or equal larger amounts of each sample (up to 5 samples are allowed) to a 25 ml glass syringe. Special precautions must be made to maintain zero headspace in the syringe.

9.2.2.2.14.4.2 The samples must be cooled at 4o C during this step to minimize volatilization losses.

9.2.2.2.14.4.3 Mix well and draw out a 5-ml aliquot for analysis.

9.2.2.2.14.4.4 Follow sample introduction, purging and desorption steps described in the method.

9.2.2.2.14.4.5 If less than five samples are used for compositing, a proportionately small syringe may be used.

9.2.2.2.14.5 Compositing samples prior to GC/MS analysis:

9.2.2.2.14.5.1 Inject 5-ml or equal larger amounts of each aqueous sample (up to 5 samples are allowed) into a 25-ml purging device using the sample introduction technique described in the method.

9.2.2.2.14.5.2 The total volume of the sample in the purging device must be 25 ml.

9.2.2.2.14.5.3 Purge and desorb as described in the method.

9.2.2.2.15 Compliance with subsection 9.2.1.3 shall be determined based on the analytical results obtained at each sampling point:

9.2.2.2.15.1 For systems which are conducting monitoring at a frequency greater than annual, compliance is determined by a running annual average of all samples taken at each sampling point. If the annual average of any sampling point is greater than the MCL, then the system is out of compliance. If the initial sample or a subsequent sample would cause the annual average to be exceeded, then the system is out of compliance immediately. Any samples below the detection limit shall be calculated as zero for purposes of determining the annual average.

9.2.2.2.15.2 If monitoring is conducted annually, or less frequently, the system is out of compliance if the level of a contaminant at any sampling point is greater than the MCL. If a confirmation sample is required by the Division, the determination of compliance will be based on the average of the two samples.

9.2.2.2.15.3 If a public water system has a distribution system separable from other parts of the distribution system with no interconnections, the Division may allow the system to give public notice to only that area served by that portion of the system which is out of compliance.

9.2.2.2.16 Analysis for the contaminants listed in subsection 9.2.1.3 shall be conducted in accordance with 40 CFR 141.24(e). Copies may be obtained from the Office of Drinking Water.

9.2.2.2.17 Analysis under this section shall only be conducted by laboratories that have received approval by EPA or the Division according to the following conditions:

9.2.2.2.17.1 To receive conditional approval to conduct analyses for the contaminants in subsection 9.2.1.3, excluding vinyl chloride, the laboratory must:

9.2.2.2.17.1.1 Analyze Performance Evaluation samples annually.

9.2.2.2.17.1.2 Achieve the quantitative acceptance limits for at least 80 percent of the regulated organic chemicals listed in subsection 9.2.1.3.

9.2.2.2.17.1.3 Achieve quantitative results on the analyses performed under subsection 9.2.2.3.16 that are within ±20 percent of the actual amount of the substances in the Performance Evaluation sample when the actual amount is greater than or equal to 0.010 mg/L.

9.2.2.2.17.1.4 Achieve quantitative results on the analyses performed under subsection 9.2.2.2.16 that are within ±40 percent of the actual amount of the substance in the Performance Evaluation sample when the actual amount is less than 0.010 mg/L.

9.2.2.2.17.1.5 Achieve a method detection limit of 0.0005 mg/L according to the procedures listed in Appendix B of 40 CFR Part 136 . Copies may be obtained from the Office of Drinking Water.

9.2.2.2.17.1.5.1 Reserved

9.2.2.2.17.2 To receive certification for vinyl chloride, the laboratory must:

9.2.2.2.17.2.1 Analyze Performance Evaluation samples annually.

9.2.2.2.17.2.2 Achieve quantitative results on the analyses performed under subsection 9.2 .2.2.17.2.1 that are within ±40 percent of the actual amount of vinyl chloride in the Performance Evaluation sample.

9.2.2.2.17.2.3 Achieve a method detection limit of 0.0005 mg/l, according to the procedures listed in Appendix B of 40 CFR Part 136. Copies may be obtained from the Office of Drinking Water.

9.2.2.2.17.2.4 Obtain certification for the contaminants listed in subsection 9.2.1.3.

9.2.2.2.18 The Division may allow the use of monitoring data collected after January 1, 1988 for purposes of initial monitoring compliance. If the data are generally consistent with the other requirements in this section, the Division may use those data (i.e., a single sample rather than four quarterly samples) to satisfy the initial monitoring requirement of subsection 9.2.2.2.4.

9.2.2.2.18.1 Systems which use grandfathered samples and did not detect any contaminant listed in subsection 9.2.1.3, excluding vinyl chloride, shall begin monitoring annually in accordance with subsection 9.2.2.2.6 beginning with the initial compliance period.

9.2.2.2.19 The Division may increase required monitoring where necessary to detect variations within the system.

9.2.2.2.20 Each approved laboratory must determine the method detection limit (MDL), as defined in Appendix B of 40 CFR Part 136, copies may be obtained from the Office of Drinking Water, at which it is capable of detecting VOCs. The acceptable MDL is 0.0005 mg/L. This concentration is the detection concentration for purposes of this section.

9.2.2.2.21 Each public water system shall monitor at the time designated by the Division within each compliance period.

9.3 Best Available Technologies (BAT)

9.3.1 The Division hereby identifies as indicated in the table below either granular activated carbon (GAC), packed tower aeration (PTA), or oxidation (OX) through chlorination or ozonation as the best technology, treatment technique, or other means available for achieving compliance with the maximum contaminant level for organic contaminants identified in subsections 9.2.1.1 and 9.2.1.3.

BAT for Organic Contaminants Listed in subsections 9.2.1.1 and 9.2.1.3

Chemical	gac	pta	ox
Alachlor		X
Atrazine		X
Benzene		X	X
Benzo(a)pyrene	X
Carbofuran		X
Carbon tetrachloride		X	X
Chlordane		X
2,4-D	X
Dalapon	X
Dibromochloropropane (DBCP)		X	X
o-Dichlorobenzene	X	X
1,2-Dichloroethane	X	X
cis-1,2-Dichloroethylene	X	X
trans-1,2-Dichloroethylene	X	X
1,1-Dichloroethylene	X	X
Dichloromethane		X
1,2-Dichloropropane	X	X
Di(2-ethylhexyl)adipate	X	X
Di(2-ethylhexyl)phthalate	X
Dinoseb	X
Diquat	X
Endothall	X
Endrin	X
Ethylene Dibromide (EDB)		X	X
Ethylbenzene		X	X
Glyphosate			X
Heptachlor		X
Heptachlor epoxide		X
Hexachlorobenzene	X
Hexachlorocyclopentadiene	X	X
Lindane		X
Methoxychlor		X
Monochlorobenzene		X	X
Oxamyl (Vydate)	X
para-Dichlorobenzene	X
Polychlorinated biphenyls (PCB)		X
Pentachlorophenol		X
Picloram		X
Simazine	X
Styrene	X
2,4,5-TP (Silvex)		X	X
Tetrachloroethylene		X	X
1,2,4-Trichlorobenzene	X	X
1,1,1-Trichloroethane	X	X
1,1,2-Trichloroethane	X	X
Trichloroethylene		X	X
Toluene		X
Toxaphene		X	X
2,3,7,8-TCDD (Dioxin)	X
Vinyl chloride		X
Xylene		X	X

BAT for Organic Contaminants Listed in subsection 9.2 .1.2

TTHM	Enhanced coagulation or enhanced softening or GAC10, with chlorine as the primary and residual disinfectant
HAA5	Enhanced coagulation or enhanced softening or GAC10, with chlorine as the primary and residual disinfectant
Bromate	Control of ozone treatment process to reduce production of bromate
Chlorite	Control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels

9.3.1.1 The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in subsection 9.2.1.2 for all systems that disinfect their source water:

Disinfection Byproduct	Best Available Technology
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5)	Enhanced coagulation or enhanced softening, plus GAC10; or nanofiltration with a molecular weight cutoff [LESS THEN OR EQUAL TO]1000 Daltons; or GAC20.]

9.3.1.2 The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or other means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in subsection 9.2.1.2 for consecutive systems and applies only to the disinfected water that consecutive systems buy or otherwise receive:

Disinfection Byproduct	Best Available Technology
Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5)	Systems serving [GREATER THEN OR EQUAL TO]10,000: Improved distribution system and storage tank management to reduce residence time, plus the use of chloramines for disinfectant residual maintenance Systems serving <10,000: Improved distribution system and storage tank management to reduce residence time

9.3.2 BAT for Inorganic Contaminants Listed in subsection 9.1.1.1

Chemical Name	BAT(s)
Antimony	2,7
Arsenic4	1,2,5,6,7,9,125
Asbestos	2,3,8
Barium	5,6,7,9
Beryllium	1,2,5,6,7
Cadmium	2,5,6,7
Chromium	2,5,62,7
Cyanide	5,7,10
Mercury	21,4,61,71
Nickel	5,6,7
Nitrate	5,7,9
Nitrite	5,7
Selenium	1,23,6,7,9
Thallium	1,5

¹ BAT only if influent Hg concentrations <10 ug/l

² BAT for Chromium III only.

³ BAT for Selenium IV only.

⁴ BAT for Arsenic V. Pre-oxidation may be required to convert Arsenic III to Arsenic V.

⁵ To obtain high removals, iron to arsenic ratio must be at least 20:1.

Key to BATs in Table

1 = Activated Alumina

2 = Coagulation/Filtration (Not BAT for systems <500 service connections)

3 = Direct and Diatomite Filtration

4 = Granular Activated Carbon

5 = Ion Exchange

6 = Lime Softening (Not BAT for systems <500 service connections)

7 = Reverse Osmosis

8 = Corrosion Control

9 = Electrodialysis

10 = Chlorine

11 = Ultraviolet

12 = Oxidation/Filtration

9.3.3 Treatment techniques for acrylamide and epichlorohydrin.

9.3.3.1 Each public water system must certify annually in writing to the Division (using a third party or manufacturer's certification) that when acrylamide and epichlorohydrin are used in drinking water systems, the combination (or product) of dose and monomer level does not exceed the levels specified as follows:

Acrylamide = 0.05% dosed at 1 PPM (or equivalent).

Epichlorohydrin = 0.01% dosed at 20 PPM (or equivalent).

9.3.4 The Administrator, U.S. Environmental Protection Agency, pursuant to section 1412 of the Safe Drinking Water Act, hereby identifies in the following table the affordable technology, treatment technique, or other means available to systems serving 10,000 persons or fewer for achieving compliance with the MCL for arsenic:

Small System Compliance Technologies (SSCTs)¹ for Arsenic²

Small system compliance technology	Affordable for listed small systems categories3
Activated Alumina (centralized)	All size categories
Activated Alumina (Point-of-Use)4	All size categories
Coagulation/Filtration5	501-3,300, 3,301-10,000
Coagulation-assisted Microfiltration	501-3,300, 3,301-10,000
Electrodialysis reversal6	501-3,300, 3,301-10,000
Enhanced Coagulation/Filtration	All size categories
Enhanced Lime Softening (pH>10.5)	All size categories
Ion Exchange	All size categories
Lime Softening5	501-3,300, 3,301-10,000
Oxidation/Filtration7	All size categories
Reverse Osmosis (centralized)6	501-3,300, 3,301-10,000
Reverse Osmosis (Point-of-Use)4	All size categories

¹ section 1412(b)(4)(E)(ii) of the Safe Drinking Water Act specifies that SSCTs must be affordable and technically feasible for small systems.

² SSCTs for Arsenic V. Preoxidation may be required to convert Arsenic III to Arsenic V.

³ The Safe Drinking Water Act specifies three categories of small systems: (i) those serving 25 or more, but fewer than 501, (ii) those serving more than 500, but fewer than 3,301, and (iii) those serving more than 3,300, but fewer than 10,001.

⁴ When POU or POE devices are used for compliance, programs to ensure proper long-term operation, maintenance, and monitoring must be provided by the water system to ensure adequate performance.

⁵ Unlikely to be installed solely for arsenic removal. May require pH adjustment to optimal range if high removals are needed.

⁶ Technologies reject a large volume of water - may not be appropriate for areas where water quantity may be an issue.

⁷ To obtain high removals, iron to arsenic ratio must be at least 20:1.

16 Del. Admin. Code § 4462-9.0

20 DE Reg. 555(1/1/2017)
20 DE Reg. 808(4/1/2017)
24 DE Reg. 794(2/1/2021) (Final)
24 DE Reg. 904( 4/1/2021) (Errata)