Wisconsin Administrative Code
Department of Natural Resources
NR 800 - Environmental Protection - Water Supply
Chapter NR 809 - Safe Drinking Water
Subchapter IV - Miscellaneous Chemical Monitoring Requirements, Raw Surface Water Standards, and Certified Laboratories
Section NR 809.74 - Additional requirements for public water systems which chlorinate or fluoridate water
Current through August 26, 2024
(1) PUBLIC WATER SYSTEMS WHICH ADD FLUORIDE.
(2) CHLORINE. The water suppliers for all waterworks which chlorinate water shall test chlorine residuals at locations and intervals necessary to control the chlorination process. At groundwater supplies, the chlorine residual of a sample from a representative location in the distribution system shall be checked at least twice per week. Water suppliers for public water systems having surface water treatment plants or GWUDI systems shall determine the chlorine residual in the plant effluent continuously and in the distribution system at least daily in representative locations. Where water quality changes rapidly, residuals shall be tested at more frequent intervals as specified by the department and in those individual cases, continuous monitoring equipment may be required if the department determines it is necessary to protect public health. Chlorine residual testing is required when bacteriological samples are taken.