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 809.32 - Groundwater microbiological source water monitoring - general requirements

(a) This section applies to all public water systems using groundwater, except for public water systems that combine all of their groundwater with surface water or with groundwater under the direct influence of surface water prior to surface water treatment.

(b) This section applies to any public water system meeting the applicability statement in sub. (1), including consecutive systems that receive finished groundwater from another public water system.

(a) Provide all information required by the department for sanitary surveys conducted under s. NR 809.35.

(b) Groundwater systems that do not treat all of their groundwater to at least 4-log treatment of viruses, using inactivation, removal, or a department-approved combination of 4-log virus inactivation and removal before or at the first customer, shall meet all the microbiological source water monitoring requirements under s. NR 809.325.

(c) Groundwater systems that have fecally contaminated source waters, as determined by source water monitoring conducted under s. NR 809.325, or have significant deficiencies that are identified by the department or that are identified by EPA, under Subpart S of 40 CFR part 141 of the U.S. Code, shall meet the treatment technique requirements in s. NR 809.327. Groundwater systems with fecally contaminated source water or with significant deficiencies are subject to the treatment technique requirements of s. NR 809.327 and shall implement one or more of the following corrective action options:

(d) Groundwater systems that provide at least 4-log treatment of viruses before or at the first customer shall conduct compliance monitoring to demonstrate treatment effectiveness, as required under s. NR 809.327(3).