Wisconsin Administrative Code
Department of Natural Resources
NR 800 - Environmental Protection - Water Supply
Chapter NR 809 - Safe Drinking Water
Subchapter II - Control of Lead and Copper
Section NR 809.544 - Source water treatment requirements for corrosion control

(a) Step 1: A water supplier for a public water system exceeding the lead or copper action level shall complete lead and copper source water monitoring under s. NR 809.549(2) and make a treatment recommendation to the department under s. NR 809.544(2) (a) no later than 180 days after the end of the monitoring period during which the lead or copper action level was exceeded.

(b) Step 2: The department shall make a determination regarding proposed source water treatment within 6 months after receipt of proposed treatment alternatives under step 1.

(c) Step 3: If the department approves installation of source water treatment, the water supplier shall install the treatment within 24 months after completion of step 2.

(d) Step 4: The water supplier shall complete follow-up tap water monitoring and source water monitoring within 36 months after completion of step 2.

(e) Step 5: The department shall review the installation and operation of source water treatment and specify maximum permissible source water levels within 6 months after completion of step 4.

(f) Step 6: The water supplier shall operate in compliance with the department-specified maximum permissible lead and copper source water levels and continue source water monitoring.

(a) Water supplier treatment recommendation. Any water supplier for a public water system that exceeds the lead or copper action level shall recommend in writing to the department the installation and operation of one of the source water treatments listed in par. (b). A water supplier may recommend that no treatment be installed based upon a demonstration that source water treatment is not necessary to minimize lead and copper levels at users' taps.

(b) Department determination regarding source water treatment. The water supplier shall complete an evaluation of the results of all source water samples collected by the water supplier to determine whether source water treatment is necessary to minimize lead or copper levels and the evaluation shall be submitted to the department. If the department determines that treatment is needed, the department shall either approve installation and operation of the source water treatment recommended by the water supplier, if any, or require the installation and operation of another source water treatment from among the following: ion exchange, reverse osmosis, lime softening or coagulation-filtration. If the department requests additional information to aid in its review, the water supplier shall provide the information by the date specified by the department in its request. The department shall notify the water supplier in writing of its determination and set forth the basis for its decision.

(c) Installation of source water treatment. Each water supplier shall properly install and operate the source water treatment approved by the department under par. (b).

(d) Department review of source water treatment and specification of maximum permissible source water levels. The department shall review the source water samples taken by the water supplier both before and after the water supplier installs source water treatment, and determine whether the water supplier has properly installed and operated the source water treatment approved by the department. Based upon its review, the department shall establish the maximum permissible lead and copper concentrations for finished water entering the distribution system. Levels shall reflect the contaminant removal capability of the treatment properly operated and maintained. The department shall notify the water supplier in writing and explain the basis for its decision.

(e) Continued operation and maintenance. Each water supplier shall maintain lead and copper levels below the maximum permissible concentrations established by the department at each sampling point monitored in accordance with s. NR 809.549. The public water system is out of compliance with this paragraph if the level of lead or copper at any sampling point is greater than the maximum permissible concentration approved by the department.

(f) Modification of department treatment decisions. Upon its own initiative or in response to a request by a water supplier or other interested party, the department may modify its determination of the source water treatment under par. (b), or maximum permissible lead and copper concentrations for finished water entering the distribution system under par. (d). A request for modification by a water supplier or other interested party shall be in writing, explain why the modification is appropriate, and provide supporting documentation. The department may modify its determination where it concludes that such change is necessary to ensure that the water supplier continues to minimize lead and copper concentrations in source water. A revised determination shall be made in writing, set forth the new treatment requirements, explain the basis for the department's decision, and provide an implementation schedule for completing the treatment modifications.

(g) Treatment decisions by EPA in lieu of the department. The EPA regional administrator may review treatment determinations made by the department under par. (b), (d) or (f) and issue federal treatment determinations consistent with the requirements of those paragraphs if the administrator finds any of the following: