General Requirements

PURPOSE: This rule gives an overview of requirements covered in the national primary drinking water regulations for lead and copper. (1) Applicability and Effective Dates. The requirements of this chapter constitute the Missouri public drinking water rules for lead and copper. Unless otherwise indicated, each of the provisions of this chapter applies to community water systems and nontransient noncommunity water systems (after this referred to as water systems or systems). (2) Scope. These rules establish a treatment technique that includes requirements for corrosion control treatment, source water treatment, lead service line replacement, and public education. These requirements are triggered, in some cases, by lead and copper action levels measured in samples collected at consumers’ taps. (3) Lead and Copper Action Levels. (A) The lead action level is exceeded if the concentration of lead in more than ten percent (10%) of tap water samples collected during any monitoring period conducted in accordance with 10 CSR 60-15.070 is greater than 0.015 milligrams/liter (mg/L) (that is, if the ninetieth percentile lead level is greater than 0.015 mg/L). (B) The copper action level is exceeded if the concentration of copper in more than ten percent (10%) of tap water samples collected during any monitoring period conducted in accordance with 10 CSR 60-15.070 is greater than 1.3 mg/L (that is, if the ninetieth percentile copper level is greater than 1.3 mg/L). (C) The ninetieth percentile lead and copper levels shall be computed as follows: 1. The results of all lead or copper samples taken during a monitoring period shall be placed in ascending order from the sample with the lowest concentration to the sample with the highest concentration. Each sampling result shall be assigned a number, ascending by single integers beginning with the number one (1) for the sample with the lowest contaminant level. The number assigned to the sample with the highest contaminant level shall be equal to the total number of samples taken; 2. The number of samples taken during the monitoring period shall be multiplied by 0.9; 3. The contaminant concentration in the numbered sample yielded by the calculation in paragraph (3)(C)2. is the ninetieth percentile contaminant level; 4. For water systems serving fewer than one hundred (100) people that collect five (5) samples per monitoring period, the ninetieth percentile is computed by taking the average of the highest and second highest concentrations; and 5. For a public water system that has been allowed by the department to collect fewer than five (5) samples in accordance with 10 CSR 60-15.070(3), the sample result with the highest concentration is considered the ninetieth percentile value. (4) Corrosion Control Treatment Requirements. (A) All water systems shall install and operate optimal corrosion control treatment as defined in 10 CSR 60-15.030. (B) Any water system that complies with the applicable corrosion control treatment requirements specified by the state under 10 CSR 60-15.020 and 10 CSR 60-15.030 shall be deemed in compliance with the treatment requirement contained in subsection (4)(A). (5) Source Water Treatment Requirements. Any system exceeding the lead or copper action level shall implement all applicable source water treatment requirements specified by the state under 10 CSR 60-15.040. (6) Lead Service Line Replacement Requirements. Any system exceeding the lead action level after implementation of applicable corrosion control and source water treatment requirements shall complete the lead service line replacement requirements contained in (7) Public Education Requirements. Pursuant to 10 CSR 60-15.060, all water systems must provide a consumer notice of lead tap water monitoring results to persons served at the sites (taps) that are tested. Any system exceeding the lead action level shall implement the public education requirements contained in 10 CSR 60-15.060. (8) Monitoring and Analytical Requirements. Tap water monitoring for lead and copper, monitoring for water quality parameters, source water monitoring for lead and copper, and analyses of the monitoring results under this section shall be completed in compliance with 10 CSR 60-15.070, 10 CSR 60-15.080, 10 CSR 60-15.090 and 10 CSR 60-5.010(1). (9) Reporting Requirements. Systems shall report to the state any information required by the treatment provisions of this section and (10) Record-keeping Requirements. Systems shall maintain records in accordance with 10 CSR 60-9.010. (11) Violation of National Primary Drinking Water Regulations. Failure to comply with the applicable requirements of 10 CSR 6015.010–10 CSR 60-15.090, 10 CSR 605.010, 10 CSR 60-7.020 and 10 CSR 609.010, including requirements established by the state pursuant to these provisions, shall constitute a violation of the state public drinking water rules for lead, copper, or both. 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.