R 325.10710c Monitoring requirements for lead and copper in source water.

Rule 710c. (1) Sample location, collection methods, and number of samples required for lead and copper monitoring in source water of community and nontransient noncommunity water supplies are as follows: (a) A water supply that fails to meet the lead or copper action level based on tap samples collected under R 325.10710a shall collect lead and copper source water samples under the following requirements regarding sample location, number of samples, and collection methods: (i) Groundwater supplies shall take a minimum of 1 sample at every entry point to the distribution system which is representative of each well after treatment, hereafter called a sampling point. The supply shall take 1 sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant. (ii) Surface water supplies shall take a minimum of 1 sample at every entry point to the distribution system after the application of treatment or in the distribution system at a point which is representative of each source after treatment, hereafter called a sampling point. The supply shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant. For purposes of this paragraph, surface water supplies include water supplies with a combination of surface and ground sources. (iii) 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, that is, when water is representative of all sources being used. (b) If the results of sampling, taken to determine compliance with R 325.10604f (4) (b) (iv), indicate an exceedance of the maximum permissible source water levels established by the department, then the department may require that 1 additional sample be collected as soon as possible after the initial sample was taken, but not more than 2 weeks later, at the same sampling point. If a department required confirmation sample is taken for lead or copper, then the results of the initial and confirmation samples shall be averaged to determine compliance with the department specified maximum permissible levels. A sample value below the detection limit shall be considered to be zero. A value above the detection limit, but below the PQL, shall either be considered as the measured value or be considered 1/2 of the PQL. (2) A water supply that exceeds the lead or copper action level at the tap shall collect 1 source water sample from each entry point to the distribution system not later than 6 months after the end of the monitoring period during which the lead or copper action level was exceeded. For monitoring periods that are annual or less frequent, the end of the monitoring period is September 30 of the calendar year in which the sampling occurs, or if the department has established an alternate monitoring period, the last day of that period. (3) A supply that installs source water treatment under R 325.10604f(4)(a)(ii) shall collect an additional source water sample from each entry point to the distribution system during 2 consecutive 6-month monitoring periods by the deadline specified in R 325.10604f(4)(a)(iii). (4) The following provisions apply to the monitoring frequency after the department specifies maximum permissible source water levels or determines that source water treatment is not needed: (a) A supply shall monitor to determine compliance with R 325.10604f(4)(b)(iv) at the frequency specified in the following paragraphs where the department specifies maximum permissible source water levels or determines that the supply is not required to install source water treatment: (i) A water supply using only groundwater shall collect samples once during the 3-year compliance period, as defined in R 325.10103, that is in effect when the applicable department determination under this subdivision is made. The supply shall collect samples once during each subsequent compliance period. Triennial samples shall be collected every third calendar year. (ii) A water supply using surface water or a combination of surface water and groundwater shall collect samples once during each calendar year. The first annual monitoring period shall begin during the year in which the applicable department determination is made under this subdivision. (b) A supply is not required to conduct source water sampling for lead or copper if the supply is in compliance with the action level for the specific contaminant in tap water samples during the entire source water sampling period applicable to the supply under subdivision (a) (i) and (ii) of this subrule. (5) Reduced monitoring frequency provisions are as follows: (a) A water supply using only groundwater may reduce the monitoring frequency for lead and copper in source water to once during each 9-year compliance cycle, as defined in R 325.10103 provided that the samples are collected not later than every ninth calendar year and if the supply meets 1 of the following criteria: (i) The supply demonstrates that finished drinking water entering the distribution system has been maintained below the department specified maximum permissible lead and copper concentrations as required in R 325.10604f(4)(b)(iv) during not less than 3 consecutive compliance periods under subrule (4)(a) of this rule. (ii) The department has determined that source water treatment is not needed and the supply demonstrates that, during not less than 3 consecutive compliance periods in which sampling was conducted under subrule (4) (a) of this rule, the concentration of lead in source water was less than or equal to 0.005 mg/l and the concentration of copper in source water was less than or equal to 0.65 mg/l. (b) A water supply using surface water or a combination of surface water and groundwater may reduce the monitoring frequency in subrule (4)(a) of this rule to once during each 9- year compliance cycle, as defined in R 325.10103 provided that the samples are collected not later than every ninth calendar year and if the supply meets either of the following criteria: (i) The supply demonstrates that finished drinking water entering the distribution system has been maintained below the department specified maximum permissible lead and copper concentrations as required in R 325.10604f(4)(b)(iv) for not less than 3 consecutive years. (ii) The department has determined that source water treatment is not needed and the supply demonstrates that, during not less than 3 consecutive years, the concentration of lead in source water was less than or equal to 0.005 mg/l and the concentration of copper in source water was less than or equal to 0.65 mg/l. (c) A water supply that uses a new source of water is not eligible for reduced monitoring for lead or copper until concentrations in samples collected from the new source during 3 consecutive monitoring periods are below the department specified maximum permissible lead and copper concentrations as required in R 325.10604f(4)(a)(iv).