NR 809.542(4)(b)(b) Step 2: The water supplier shall complete corrosion control studies and submit option for optimal corrosion control treatment to the department by July 1, 1994.

NR 809.542(4)(g)(g) Step 7: The water supplier shall operate in compliance with the department-approved optimal water quality control parameters and continue to conduct tap sampling.

NR 809.542(5)(5) Treatment steps and deadlines for small and medium-size systems. Except as provided in sub. (2), water suppliers for small and medium-size systems shall complete the following corrosion control treatment steps by the indicated time periods:

NR 809.542(5)(a)(a) Step 1: The water supplier shall conduct initial tap sampling until the public water system either exceeds the lead or copper action level or becomes eligible for reduced monitoring under s. NR 809.547 (4) (d). A water supplier exceeding the lead or copper action level shall recommend optimal corrosion control treatment, under s. NR 809.543 (1), within six months after the end of the monitoring period during which the public water system exceeds one of the action levels.

NR 809.542(5)(b)(b) Step 2: Within 12 months after the end of the monitoring period during which a public water system exceeds the lead or copper action level, the department may require the water supplier to perform corrosion control studies, under s. NR 809.543 (2). If the department does not require the water supplier to perform such studies, the department shall specify optimal corrosion control treatment, under s. NR 809.543 (4) within the following timeframes:

NR 809.542(5)(b)1.1. For medium-size systems, within 18 months after the end of the monitoring period during which such public water system exceeds the lead or copper action level.

NR 809.542(5)(c)(c) Step 3: If the department requires a water supplier to perform corrosion control studies under step 2, the water supplier shall complete the studies within 18 months after the department requires the studies be conducted.

NR 809.542(5)(d)(d) Step 4: If the water supplier has performed corrosion control studies under step 2, the department shall review and determine adequacy of public water system’s optimal corrosion control treatment within 6 months after completion of step 3.

NR 809.542(5)(g)(g) Step 7: The department shall review the installation of treatment and approve optimal water quality control parameters within 6 months after completion of step 6.

NR 809.542(5)(h)(h) Step 8: The water supplier shall operate in compliance with the department-approved optimal water quality control parameters and continue to conduct tap sampling.

NR 809.542 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; correction in (2) (c) made under s. 13.92 (4) (b) 7., Stats., Register November 2010 No. 659; CR 15-049: am. (2) (c) 3. Register March 2016 No. 723, eff. 4-1-16; correction in (5) (b) made under s. 13.92 (4) (b) 7., Stats., Register July 2022 No. 799.

NR 809.543NR 809.543 Description of corrosion control treatment requirements. Each water supplier shall complete the following corrosion control treatment requirements which are applicable to their public water system under s. NR 809.542.

NR 809.543(1)(1) Water supplier recommendation regarding corrosion control treatment. Based upon the results of lead and copper tap monitoring and water quality parameter monitoring, water supplier for a small and medium-size water systems exceeding the lead or copper action level shall recommend installation of one or more of the corrosion control treatments listed in sub. (3) (a) which the water supplier believes constitutes optimal corrosion control for that public water system. The department may require the water supplier to conduct additional water quality parameter monitoring in accordance with s. NR 809.548 (2) to assist the department in reviewing the water supplier’s recommendation. In no case may the time period for installation of optimal corrosion control treatment on a small or medium-size system exceed the schedule as listed in s. NR 809.542 (5) (a) to (h).

NR 809.543(2)(2) Department decision to require studies of corrosion control treatment by small and medium-size systems. The department may require the water supplier of any small or medium-size system that exceeds the lead or copper action level to perform corrosion control studies under sub. (3) to identify optimal corrosion control treatment for the public water system.

NR 809.543(3)(3) Performance of corrosion control studies.

NR 809.543(3)(a)(a) Any water supplier performing corrosion control studies shall evaluate the effectiveness of each of the following treatments, and, if appropriate, combinations of the following treatments to identify the optimal corrosion control treatment for that public water system:

NR 809.543(3)(a)3.3. The addition of a phosphate or silicate based corrosion inhibitor at a concentration sufficient to maintain an effective residual concentration in all test tap samples.

NR 809.543(3)(b)(b) The water supplier shall evaluate each of the corrosion control treatments listed in par. (a) using either pipe rig or loop tests, metal coupon tests, partial-system tests, or analyses based on documented analogous treatments with other public water systems of similar size, water chemistry and distribution system configuration.

NR 809.543(3)(c)(c) The water supplier shall measure all of the following water quality parameters in any tests conducted before and after evaluating the corrosion control treatments listed in par. (a):