Mich. Admin. Code R. 325.10710b

Current through Vol. 24-21, December 1, 2024

Section R. 325.10710b - Monitoring requirements for water quality parameters

Rule 710b.

(1) The requirements of this rule are summarized in table 1 of this rule. The following community and nontransient noncommunity water supplies, which are considered "water supplies" or "supplies" in this rule, shall monitor for water quality parameters in addition to lead and copper under this rule:

(a) Large water supplies.

(b) Small and medium size water supplies that exceed the lead or copper action level or have optimal corrosion control treatment installed.

(2) Sample collection methods provisions are as follows:

(a) Tap samples shall be representative of water quality throughout the distribution system taking all of the following factors into account:

(i) The number of persons served.

(ii) The different sources of water.

(iii) The different treatment methods employed by the supply.

(iv) Seasonal variability. Tap sampling under this subdivision is not required to be conducted at taps targeted for lead and copper sampling under R 325.10710a(1)(b). Samples collected at the entry point or points to the distribution system shall be from locations that are representative of each source after treatment. If a supply draws water from more than 1 source and the sources are combined before distribution, the supply shall sample at an entry point to the distribution system during periods of normal operating conditions, for example, when water is representative of all sources being used.

(3) The number of samples a supply is required to collect are as follows:

(a) A supply shall collect 2 tap samples for applicable water quality parameters during each monitoring period specified in subrules (4) to (7) of this rule from the following number of sites:

Supply Size (Number of People Served)	Number of Sites for Water Quality Parameters
More than 100,000	25
10,001 to 100,000	10
3,301 to 10,000	3
501 to 3,300	2
101 to 500	1
Fewer than 101	1

(b) Except as provided in subrule (5)(c) of this rule, a water supply shall collect 2 samples for each applicable water quality parameter at each entry point to the distribution system during each monitoring period specified in subrule (4) of this rule. During each monitoring period specified in subrules (5) to (7) of this rule, a supply shall collect 1 sample for each applicable water quality parameter at each entry point to the distribution system.

(4) A large water supply shall measure the applicable water quality parameters, at the locations specified in the following subdivisions at taps and at each entry point to the distribution system during each 6-month monitoring period specified in R 325.10710a(4)(a). A small or medium size water supply shall measure the applicable water quality parameters at the locations specified in the following subdivisions during each 6-month monitoring period, as specified in R 325.10710a(4)(a), that the supply exceeds the lead or copper action level or if optimal corrosion control treatment is installed:

(a) At taps, a water supply shall measure each of the following:

(i) pH.

(ii) Alkalinity.

(iii) Orthophosphate, when an inhibitor containing a phosphate compound is used.

(iv) Silica, when an inhibitor containing a silicate compound is used.

(v) Calcium.

(vi) Conductivity.

(vii) Water temperature.

(viii) Sulfate.

(ix) Chloride.

(b) At each entry point to the distribution system, a water supply shall measure each of the applicable parameters that are listed in subdivision (a) of this subrule.

(5) A large water supply that installs optimal corrosion control treatment under R 325.10604f(2)(d)(iii) shall measure the water quality parameters at the locations and frequencies specified in this subrule during each 6-month monitoring period specified in R 325.10710a(4)(b)(i). A small or medium size water supply that installs optimal corrosion control treatment shall measure the water quality parameters at the locations specified in the following during each 6-month monitoring period, as specified in R 325.10710a(4)(b)(ii):

(a) At taps, 2 samples for each of the following:

(i) pH.

(ii) Alkalinity.

(iii) Orthophosphate, when an inhibitor containing a phosphate compound is used.

(iv) Silica, when an inhibitor containing a silicate compound is used.

(v) Calcium, when calcium carbonate stabilization is used as part of the corrosion control.

(vi) Sulfate.

(vii) Chloride.

(b) Except as provided in subdivision (c) of this subrule, at each entry point to the distribution system, at least 1 sample at least every 2 weeks for each of the following:

(i) pH.

(ii) When alkalinity is adjusted as part of optimal corrosion control, a reading of the dosage rate of the chemical used to adjust alkalinity and a reading of the alkalinity concentration.

(iii) When a corrosion inhibitor is used as part of optimal corrosion control, a reading of the dosage rate of the inhibitor used and a reading of the concentration of orthophosphate or silica, whichever is applicable.

(iv) Sulfate.

(v) Chloride.

(c) A ground water supply may limit entry point sampling described in subdivision (b) of this subrule to those entry points that are representative of water quality and treatment conditions throughout the system. If water from untreated ground water sources mixes with water from treated ground water sources, the supply shall monitor for water quality parameters both at representative entry points receiving treatment and representative entry points receiving no treatment. Before the start of the monitoring under this subdivision, the supply shall provide to the department written information identifying the selected entry points and documentation, including information on seasonal variability, sufficient to demonstrate that the sites are representative of water quality and treatment conditions throughout the system.

(6) After the department specifies the values for applicable water quality control parameters reflecting optimal corrosion control treatment under R 325.10604f(3)(f), water supplies shall measure the applicable water quality parameters under subrule (5) of this rule and determine compliance with the requirement of R 325.10604f(3)(g) every 6 months with the first 6-month period to begin on either January 1 or July 1, whichever comes first, after the department specifies the optimal values under R 325.10604f(3)(f). Compliance with department designated optimal water quality parameter values shall be determined as specified under R 325.10604f(3)(g).

(7) Reduced monitoring provisions are as follows:

(a) A supply that maintains the range of values for the water quality parameters reflecting optimal corrosion control treatment during each of 2 consecutive 6-month monitoring periods under subrule (6) of this rule shall continue monitoring applicable water quality parameters at the locations and frequencies specified in subrule (5) of this rule. The supply may reduce the number of sites from which it monitors during each 6-month monitoring period to the following:

Supply Size (Number of People Served)	Reduced Number of Sites For Water Quality Parameters
More than 100,000	10
10,001 to 100,000	7
3,301 to 10,000	3
501 to 3,300	2
101 to 500	1
Fewer than 101	1

(b) A water supply that maintains the range of values for the water quality parameters reflecting optimal corrosion control treatment specified by the department under R 325.10604f(3)(f) during 3 consecutive years of monitoring specified in this subdivision may reduce the frequency with which it collects the number of tap samples for applicable water quality parameters specified in subdivision (a) of this subrule from every 6 months to annually. This sampling begins during the calendar year immediately following the end of the monitoring period in which the third consecutive year of 6-month monitoring occurs.

(c) A water supply that conducts sampling annually shall collect the samples evenly throughout the year to reflect seasonal variability.

(d) A water supply subject to the reduced monitoring frequency that fails to operate at or above the minimum value or within the range of values for the water quality parameters specified by the department for more than 9 days in a 6-month period specified in R 325.10604f(3)(g) shall resume distribution system tap water sampling under the number and frequency requirements specified in subrule (6) of this rule. The supply may resume annual monitoring for water quality parameters at the tap at the reduced number of sites specified in subdivision (a) of this subrule after it has completed 2 subsequent consecutive 6-month rounds of monitoring that meet the criteria of that subdivision.

(8) The results of monitoring conducted in addition to the minimum requirements of this rule shall be considered in determining the concentrations of water quality parameters.

(9) Table 1 of this rule reads as follows:

Table 1 Summary of Monitoring Requirements for Water Quality Parameters - Lead, Copper, Corrosion Control¹

Monitoring Period	Parameters	Location	Frequency
Initial monitoring	pH, alkalinity, orthophosphate or silica 2, calcium, conductivity, temperature, sulfate, chloride	Taps and at entry point or points to distribution system	6 months
After installation of corrosion control	pH, alkalinity, orthophosphate or silica2, calcium3	Taps	Every 6 months
	pH, alkalinity dosage rate and concentration (if alkalinity adjusted as part of corrosion control), inhibitor dosage rate and inhibitor residual 4, sulfate, chloride	Entry point or points to distribution system5	At least every 2 weeks
After department specifies parameter values for optimal corrosion control	pH, alkalinity, orthophosphate or silica2, calcium3	Taps	Every 6 months
	pH, alkalinity dosage rate and concentration (if alkalinity adjusted as part of corrosion control), inhibitor dosage rate and inhibitor residual 4, sulfate, chloride	Entry point or points to distribution system5	At least every 2 weeks
Reduced monitoring	pH, alkalinity, orthophosphate or silica 2, calcium 3	Taps	Every 6 months annually 6 at a reduced number of sites
	pH, alkalinity dosage rate and concentration (if alkalinity adjusted control), inhibitor dosage rate and inhibitor residual 4, sulfate, chloride	Entry point or points to distribution system5	At least every 2 weeks

¹ Table is for illustrative purposes; consult the text of this part for precise regulatory requirements.

² Orthophosphate shall be measured when an inhibitor containing a phosphate compound is used. Silica shall be measured when an inhibitor containing silicate compound is used.

³ Calcium shall be measured when calcium carbonate stabilization is used as part of corrosion control.

⁴ Inhibitor dosage rates and inhibitor residual concentrations (orthophosphate or silica) shall be measured when an inhibitor is used.

⁵ Ground water supplies may limit monitoring to representative locations throughout the system.

⁶ Water supplies may reduce frequency of monitoring for water quality parameters at the tap from every 6 months to annually if they have maintained the range of values for water quality parameters reflecting optimal corrosion control during 3 consecutive years of monitoring.

Mich. Admin. Code R. 325.10710b

1994 AACS; 1998 AACS; 2002 AACS; 2009 AACS; 2018 MR 11, Eff. 6/14/2018