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 809.328 - Treatment technique compliance for groundwater source microbiological contaminants

(a) A groundwater system with a significant deficiency is in violation of the treatment technique requirement if, within 120 days of the water supplier receiving written notice from the department of the significant deficiency or earlier if directed by the department, subd. 1. or 2. are not met.

(b) Unless the department invalidates an E. coli-positive groundwater source sample collected under s. NR 809.325, a public water system is in violation of the treatment technique requirement under s. NR 809.327 if within 120 days or earlier if directed by the department, the conditions of subd. 1. or 2 are not met.

(c) A water supplier for a groundwater system subject to the requirements of s. NR 809.327(4) that fails to maintain at least 4-log treatment of viruses before or at the first customer for a groundwater source is in violation of the treatment technique requirement if the failure is not corrected within 4 hours of determining the public water system is not maintaining at least 4-log treatment of viruses before or at the first customer.