Source Water Treatment Requirements

PURPOSE: This rule describes the required corrosion control treatment steps for a system’s source water and establishes treatment requirement deadlines. (1) The following are deadlines for completing source water treatment steps: (A) A system exceeding the lead or copper action level shall complete lead and copper source water monitoring under 10 CSR 6015.090(2) and make a treatment recommendation to the department no later than one hundred eighty (180) days after the end of the monitoring period during which the lead or copper action level was exceeded; (B) The department shall make a determination regarding source water treatment within six (6) months after submission of monitoring results under subsection (1)(A) of this rule; (C) If the department requires installation of source water treatment, the system shall install the treatment within twenty-four (24) months after the completion of subsection (1)(B) of this rule; (D) The system shall complete follow-up tap water monitoring and source water monitoring within thirty-six (36) months after completion of subsection (1)(B) of this rule; (E) The department shall review the system’s installation and operation of source water treatment and specify maximum permissible source water levels within six (6) months after completion of subsection (1)(D) of this rule; (F) The system shall operate in compliance with the department-specified maximum permissible lead and copper source water levels and continue source water monitoring. (2) Any system which exceeds the lead or copper action level shall recommend in writing to the department the installation and operation of one (1) of the source water treatments listed in the following subsections. A system 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: (A) The department shall complete an evaluation of the results of all source water samples submitted by the water system to determine whether source water treatment is necessary to minimize lead or copper levels in water delivered to users’ taps. If the department determines that treatment is needed, the department shall either require installation and operation of the source water treatment recommended by the system, if any, or require the installation and operation of another source water treatment from the following: ion exchange, reverse osmosis, lime softening, or coagulation/filtration. If the department requests additional information to aid in its review, the water system shall provide the information by the date specified by the department in its request. The department shall notify the system in writing of its determination and set forth the basis for its decision; (B) Each system shall properly install and operate the source water treatment designated by the department; (C) The department shall review the source water samples taken by the water system both before and after the system installs source water treatment, and determine whether the system has properly installed and operated the source water treatment designated by the department. Based upon its review, the department shall designate the maximum permissible lead and copper concentrations for finished water entering the distribution system. These levels shall reflect the contaminant removal capability of the treatment properly operated and maintained. The department shall notify the system in writing and explain the basis for its decision; (D) Each water system shall maintain lead and copper levels below the maximum permissible concentrations designated by the department at each sampling point monitored in accordance with 10 CSR 60-15.090. The system is out of compliance if the level of lead or copper at any of the sampling points are greater than the maximum permissible concentration designated by the department; or (E) The department, upon its own initiative or in response to a request by a water system or other interested party, may modify its determination of the source water treatment or maximum permissible lead and copper concentrations for finished water entering the distribution system. A request for modification by a system 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 the change is necessary to ensure that the system continues to minimize lead and copper concentrations in the 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. AUTHORITY: section 640.100, RSMo Supp. 2011.* Original rule filed Aug. 4, 1992, effective May 6, 1993. Amended: Filed Oct. 17, 2011, effective May 30, 2012. *Original authority: 640.100, RSMo 1939, amended 1978, 1981, 1982, 1988, 1989, 1992, 1993, 1995, 1996, 1998, 1999, 2002, 2006.