Wisconsin Administrative Code
Department of Natural Resources
NR 800 - Environmental Protection - Water Supply
Chapter NR 809 - Safe Drinking Water
Subchapter I - Maximum Contaminant Levels, Monitoring and Analytical Requirements for Primary Drinking Water Contaminants
Section NR 809.247 - Compliance requirements for volatile organic contaminants

Universal Citation: WI Admin Code § NR 809.247

Current through August 26, 2024

(1) MCL COMPLIANCE DETERMINATION. Compliance with volatile organic contaminant MCLs shall be determined as follows:

(a) Compliance with the VOC MCLs specified in s. NR 809.24 shall be determined based on the analytical results obtained at each entry point. If one entry point is in violation of an MCL, the public water system is in violation of the MCL.

(b) For public water systems which are monitored more frequently than annually, compliance is determined by a running annual average of all samples taken at each entry point. If the annual average of any entry point is greater than the MCL, the public water system is out of compliance. If the initial sample or a subsequent sample would cause the annual average to exceed the MCL, the public water system is out of compliance immediately.

(c) If monitoring is conducted annually, or less frequently, the public water system is out of compliance if the level of a contaminant at any entry point is greater than the MCL. Compliance shall be based on the concentration of this sample or the average value of this sample and the confirmation sample, if the department required a confirmation sample.

(d) If a water supplier fails to collect the required number of samples, compliance shall be based on the total number of samples collected.

(e) Any concentration reported at or above the method detection limit for any contaminant listed in s. NR 809.24 shall be used in determining the averages in pars. (b) and (c). Any concentration reported below the method detection limit shall be calculated at zero for the purposes of determining the averages in pars. (b) and (c).

(2) DETECTION OF VOLATILE CONTAMINANTS NOT LISTED IN S. NR 809.24. Any detection of a volatile organic contaminant not listed in s. NR 809.24 shall be reported to the department with the other monitoring reports required under this section. The laboratory shall indicate whether any detected volatile organic contaminant not listed in s. NR 809.24 has been confirmed or tentatively identified, and when a numerical result is reported, whether the result is quantitative or an estimate.

(3) SEPARATE DISTRIBUTION SYSTEM NOTICE. If a public water system has a distribution system separable from other parts of the distribution system with no interconnections, the department may allow the water supplier to give public notice to only that area served by that portion of the public water system which is out of compliance.

(4) USE OF ANALYTICAL RESULTS. The department may determine compliance or initiate enforcement action based upon analytical results and other information compiled by its sanctioned representatives and agencies.

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