NR 809.542(2)(c)1.1. The department may deem that public water systems whose highest source water lead level is below method detection limit have optimized corrosion control under this subsection if the 90th percentile tap water lead level is less than or equal to the practical quantitation level for 2 consecutive 6-month monitoring periods. NR 809.542(2)(c)2.2. Any public water system deemed to have optimized corrosion control in accordance with this subsection shall continue monitoring for lead and copper at the tap no less frequently than once every 3 calendar years using the reduced number of sites specified in s. NR 809.547 (3) and collecting the samples at times and locations specified in s. NR 809.547 (4) (d) 4. Any water supplier for a public water system that has not conducted a round of monitoring pursuant to s. NR 809.547 (4) (d) since September 30, 1997, shall complete a round of monitoring pursuant to this subsection as specified by the department. NR 809.542(2)(c)3.3. Any water suppliers for a public water system deemed to have optimized corrosion control pursuant to this paragraph shall notify the department in writing pursuant to s. NR 809.55 (1) (c) 3. of any upcoming long-term change in treatment or addition of a new source as described in that section. The department shall review and approve the addition of a new source or long-term change in water treatment before it is implemented by the water supplier. The department may require any water supplier to conduct additional monitoring or to take other action the department deems appropriate to ensure that the water supplier maintains minimal levels of corrosion in the distribution system. NR 809.542(2)(c)4.4. As of December 1, 2002, a public water system is not deemed to have optimized corrosion control under this subsection, and the water supplier shall implement corrosion control treatment pursuant to subd. 5. unless the public water system meets the copper action level. NR 809.542(2)(c)5.5. Any public water system triggered into corrosion control because it is no longer deemed to have optimized corrosion control under this subsection shall implement corrosion control treatment in accordance with the deadlines in sub. (5). Any large system shall adhere to the schedule specified in that paragraph for medium-size systems, with the time periods for completing each step being triggered by the date the public water system is no longer deemed to have optimized corrosion control under this subsection. NR 809.542(3)(3) Criteria for completing corrosion control treatment studies for small and medium-size systems. Any water supplier for a small or medium-size water system that is required to complete the corrosion control steps due to the exceedance of the lead or copper action level may cease completing the treatment steps whenever the public water system meets both action levels during each of 2 consecutive monitoring periods conducted pursuant to s. NR 809.547 and the results are submitted to the department. If any such public water system thereafter exceeds the lead or copper action level during any monitoring period, the water supplier shall recommence completion of the applicable treatment steps, beginning with the first treatment step which was not previously completed in its entirety. The department may require a water supplier to repeat treatment steps previously completed by the water supplier if the department determines that this is necessary to properly implement the treatment requirements. The department shall notify the water supplier in writing of such a determination and explain the basis for its decision. The water supplier for a small or medium-size water system shall implement corrosion control treatment steps in accordance with sub. (5), including a public water system deemed to have optimized corrosion control under sub. (2) (a), whenever it exceeds the lead or copper action level. NR 809.542(4)(4) Treatment steps and deadlines for large systems. Except as provided in sub. (2) (b) and (c), water suppliers for large systems shall complete the following corrosion control treatment steps by the indicated dates: NR 809.542(4)(a)(a) Step 1: The water supplier shall conduct initial monitoring during 2 consecutive 6-month monitoring periods by January 1, 1993. 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)(c)(c) Step 3: The department shall approve optimal corrosion control treatment by January 1, 1995. NR 809.542(4)(d)(d) Step 4: The water supplier shall install optimal corrosion control treatment by January 1, 1997. NR 809.542(4)(e)(e) Step 5: The water supplier shall complete follow-up sampling by January 1, 1998. NR 809.542(4)(f)(f) Step 6: The department shall review installation of treatment and approve optimal water quality control parameters by July 1, 1998. 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)(b)2.2. For small systems, within 24 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)(e)(e) Step 5: The water supplier shall install optimal corrosion control treatment within 24 months after the department approves the treatment. NR 809.542(5)(f)(f) Step 6: The water supplier shall complete follow-up sampling within 36 months after the department approves optimal corrosion control treatment. 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)(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): NR 809.543(3)(c)7.7. Orthophosphate (when an inhibitor containing a phosphate compound is used). NR 809.543(3)(d)(d) The water supplier shall identify all chemical or physical constraints that limit or prohibit the use of a particular corrosion control treatment and document such constraints with at least one of the following: NR 809.543(3)(d)1.1. Data and documentation showing that a particular corrosion control treatment has adversely affected other water treatment processes when used by another public water system with comparable water quality characteristics. NR 809.543(3)(d)2.2. Data and documentation demonstrating that the water supplier has previously attempted to evaluate a particular corrosion control treatment and has found that the treatment is ineffective or adversely affects other water quality treatment processes, or both. NR 809.543(3)(e)(e) The water supplier shall evaluate the effect of the chemicals used for corrosion control treatment on other water quality treatment processes. NR 809.543(3)(f)(f) On the basis of an analysis of the data generated during each evaluation, the water supplier shall recommend to the department in writing the treatment option that the corrosion control studies indicate constitutes optimal corrosion control treatment for that public water system. The water supplier shall provide a rationale for its recommendation along with all supporting documentation specified in pars. (a) to (e). NR 809.543(4)(4) Department evaluation of optimal corrosion control treatment. NR 809.543(4)(a)(a) Based upon consideration of available information including, where applicable, studies performed under sub. (3) and a water supplier’s recommended treatment alternative, the department shall either approve the corrosion control treatment option recommended by the water supplier, or designate alternative corrosion control treatments from among those listed in sub. (3) (a). When approving optimal treatment, the department shall consider the effects that additional corrosion control treatment will have on water quality parameters and on other water quality treatment processes. NR 809.543(4)(b)(b) The department shall notify the water supplier of its decision on optimal corrosion control treatment in writing and explain the basis for this determination. If the department requests additional information to aid its review, the water supplier shall provide the information. NR 809.543(5)(5) Installation of optimal corrosion control. Each water supplier shall properly install and operate throughout the public water system’s distribution system the optimal corrosion control treatment approved by the department under sub. (4). NR 809.543(6)(6) Department review of treatment. The department shall evaluate the results of all lead and copper tap samples and water quality parameter samples submitted by the water supplier and determine whether the water supplier has properly installed and operated the optimal corrosion control treatment approved by the department in sub. (4). Upon reviewing the results of tap water and water quality parameter monitoring by the water supplier, both before and after the water supplier installs optimal corrosion control treatment, the department shall establish ranges for water quality parameters. NR 809.543(7)(7) Approval of optimal water quality control parameters. The department shall review the water supplier’s recommendations and select the values for the applicable water quality control parameters listed in sub. (3) which reflect optimal corrosion control treatment for the public water system. The department may specify values for additional water quality control parameters to reflect optimal corrosion control for the public water system. The department shall notify the water supplier in writing of these determinations and explain the basis for its decision. At a minimum, the department shall establish all of the following: NR 809.543(7)(a)(a) A minimum value or a range of values for pH measured at each entry point to the distribution system. NR 809.543(7)(b)(b) A minimum pH value, measured in all tap samples. The value shall be equal to or greater than 7.0, unless the water supplier provides information to indicate that meeting a pH level of 7.0 is not technologically feasible or is not necessary for the public water system to optimize corrosion control. NR 809.543(7)(c)(c) If a corrosion inhibitor is used, a minimum concentration or a range of concentrations for the inhibitor, measured at each entry point to the distribution system and in all tap samples, that the department determines is necessary to protect the interior walls of the pipes of the distribution system from corrosion. 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(7)(e)(e) If calcium carbonate stabilization is used as part of corrosion control, a minimum concentration or a range of concentrations for calcium, measured 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)(b)(b) On days when only one measurement for the water quality parameter is collected at the sampling location, the daily value shall be the result of that measurement. 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 809.543(10)(a)(a) The department has failed to issue a treatment determination by the applicable deadlines contained in s. NR 809.542. NR 809.543(10)(b)(b) The department has abused its discretion in a substantial number of cases or in cases affecting a substantial population. NR 809.543(10)(c)(c) The technical aspects of the department’s determination would be indefensible in an expected federal enforcement action taken against a water supplier. NR 809.543 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; correction in (8) (intro.) made under s. 13.92 (4) (b) 7., Stats., Register November 2010 No. 659. NR 809.544NR 809.544 Source water treatment requirements for corrosion control. 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(1)(b)(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. NR 809.544(1)(c)(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. NR 809.544(1)(d)(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. NR 809.544(1)(e)(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. NR 809.544(1)(f)(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. 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)(c)(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). 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: NR 809.544(2)(g)1.1. The department has failed to issue a treatment determination by the applicable deadlines contained in sub. (1). NR 809.544(2)(g)2.2. The department has abused its discretion in a substantial number of cases or in cases affecting a substantial population.
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