Section 809.549. Monitoring requirements for lead and copper in source water.

 

(1)   Sample location, collection methods and number of samples.

(a) The water supplier of a public water system that fails to meet the lead or copper action level on the basis of tap samples collected in accordance with s. NR 809.547 shall collect lead and copper source water samples in accordance with the requirements regarding sample location, number of samples and collection methods:

1. The water suppliers for 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. The water supplier shall take one sample at the same sampling location unless conditions make another sampling location more representative of each source or treatment plant.

2. The water suppliers for 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. The water supplier shall take each sample at the same sampling location unless conditions make another sampling location more representative of each source or treatment plant. For the purposes of this paragraph, surface water systems include public water systems with a combination of surface water and groundwater sources.

3. If a public water system draws water from more than one source and the sources are combined before distribution, the water supplier shall sample at an entry point to the distribution system during periods of normal operating conditions, and when water is representative of all sources being used.

4. The department may reduce the total number of samples which are to be analyzed by allowing the use of compositing. Compositing of samples shall be done by certified laboratory personnel. Composite samples from a maximum of 5 samples are allowed, provided that if the lead concentration in the composite sample is greater than or equal to 0.001 mg/L or the copper concentration is greater than or equal to 0.160 mg/ L, one of the following applies:

a. A follow-up sample shall be taken and analyzed within 14 days at each sampling point included in the composite.

b. If duplicates of or sufficient quantities from the original samples from each sampling point used in the composite are available, the water supplier may use these instead of resampling.

(b) Where the results of sampling indicate an exceedance of maximum permissible source water levels established under s. NR 809.544 (2) (d) , the department may require that one additional sample be collected as soon as possible after the initial sample was taken, but not to exceed 2 weeks, 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 sample shall be averaged in determining compliance with the department-specified maximum permissible levels. Any sample value below the detection limit shall be considered to be zero. Any value above the detection limit but below 5 ug/l, shall be considered as the measured value.

(2)   Monitoring frequency after a public water system exceeds tap water action level. A water supplier for any public water system which exceeds the lead or copper action level at the tap shall collect one source water sample from each entry point to the distribution system no later than six 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)   Monitoring frequency after installation of source water treatment. Any water supplier which installs source water treatment pursuant to s. NR 809.544 (1) (b) 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 s. NR 809.544 (1) (d) .

(4)   Monitoring frequency after department specifies maximum permissible source water levels or determines that source water treatment is not needed.

(a) A water supplier shall monitor at the frequency specified below in cases where the department specifies maximum permissible source water levels under s. NR 809.544 (2) (d) or determines that the water supplier is not required to install source water treatment under s. NR 809.544 (2) (b) .

1. A water supplier of a public water system using only groundwater shall collect samples once during the 3-year compliance period in effect when the applicable department determination under par. (a) is made. The water supplier shall collect samples once during each subsequent compliance period. Triennial samples shall be collected every third calendar year.

2. A water supplier for a public water system using surface water, or a combination of surface and groundwater, shall collect samples once during each calendar year, the first annual monitoring period to begin during the year in which the applicable department determination is made under sub. (4) (a) .

(b) A water supplier is not required to conduct source water sampling for lead or copper, or both, if the public water system meets the action level for the specific contaminant in tap water samples during the entire source water sampling period applicable to the public water system under par. (a) 1. or 2.

(5)   Reduced monitoring frequency.

(a) A water supplier for a public water system using only groundwater may reduce the monitoring frequency for lead and copper in source water to once during each compliance cycle provided that the samples are collected no later than every ninth calendar year and if the public water system meets one of the following criteria:

1. The water supplier for a public water system demonstrates that the finished drinking water entering the distribution system has been maintained below the maximum permissible lead and copper concentrations specified by the department in s. NR 809.544 (2) (d) during at least 3 consecutive compliance periods under sub. (4) (a) .

2. The department has determined that source water treatment is not needed and the water supplier for a public water system demonstrates that, during at least 3 consecutive compliance periods in which sampling was conducted under sub. (4) (a) , 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 supplier for a public water system using surface water, or a combination of surface water and groundwater may reduce the monitoring frequency in sub. (4) (a) to once during each compliance cycle provided that the samples are collected no later than every ninth calendar year and if the public water system meets one of the following criteria:

1. The water supplier for the public water system demonstrates that finished drinking water entering the distribution system has been maintained below the maximum permissible lead and copper concentrations specified by the department in s. NR 809.544 (2) (d) for at least 3 consecutive years.

2. The department has determined that source water treatment is not needed and the water supplier for the public water system demonstrates that, during at least 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 public water system that uses a new source of water is not eligible for reduced monitoring for lead or copper, or both, until concentrations in samples collected from the new source during 3 consecutive monitoring periods are below the maximum permissible lead and copper concentrations specified by the department in s. NR 809.544 (1) (e) .

CR 09-073 : cr. Register November 2010 No. 659 , eff. 12-1-10.