NR 809.543(7)(d)(d) If alkalinity is adjusted as part of optimal corrosion control treatment, a minimum concentration or a range of concentrations for alkalinity, measured at each entry point to the distribution system and in all tap samples.

NR 809.543(8)(8) Continued operation and monitoring. All water suppliers optimizing corrosion control shall continue to operate and maintain optimal corrosion control treatment, including maintaining water quality parameters at or above minimum values or within ranges designated by the department under sub. (7), in accordance with this subsection for all samples collected under s. NR 809.548 (4). Compliance with the requirements of this subsection shall be determined every 6 months, as specified under s. NR 809.548 (4). A public water system is out of compliance with the requirements of this subsection for a 6-month period if it has excursions for any department-specified parameter on more than 9 days during the period. An excursion occurs whenever the daily value for one or more of the water quality parameters measured at a sampling location is below the minimum value or outside the range designated by the department. The department may delete results of obvious sampling errors from this calculation. Daily values are calculated as follows:

NR 809.543(8)(a)(a) On days when more than one measurement for the water quality parameter is collected at the sampling location, the daily value shall be the average of all results collected during the day regardless of whether they are collected through continuous monitoring, grab sampling or a combination of both. If EPA has approved an alternative formula under 40 CFR 142.16 in the department’s application for a program revision submitted pursuant to 40 CFR 142.12, the department’s formula shall be used to aggregate multiple measurements taken at a sampling point for the water quality parameter in lieu of the formula in this paragraph.

NR 809.543(8)(c)(c) On days when no measurement is collected for the water quality parameter at the sampling location, the daily value shall be the daily value calculated on the most recent day on which the water quality parameter was measured at the sample site.

NR 809.543(9)(9) 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 optimal corrosion control treatment under sub. (4) or optimal water quality control parameters under sub. (6). 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 if it concludes that a change is necessary to ensure that the water supplier continues to optimize corrosion control treatment. 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.

NR 809.543(10)(10) Treatment decisions by epa in lieu of the department. The EPA regional administrator may review treatment determinations made by the department under sub. (4), (6) or (8) and issue federal treatment determinations consistent with the requirements of those subsections if the regional administrator finds any of the following:

NR 809.544(1)(1) Deadlines for completing source water treatment steps. Water suppliers shall complete the applicable source water monitoring and treatment requirements by the following deadlines:

NR 809.544(1)(a)(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.

NR 809.544(2)(2) Description of source water treatment requirements.

NR 809.544(2)(a)(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.

NR 809.544(2)(b)(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.

NR 809.544(2)(d)(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.

NR 809.544(2)(e)(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.

NR 809.544(2)(f)(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.

NR 809.544(2)(g)(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: