Missouri Code of State Regulations › Title 10 - DEPARTMENT OF NATURAL RESOURCES › Division 60 - Safe Drinking Water Commission › Chapter 15 - Lead and Copper › Section 10 CSR 60-15.010 - General Requirements

Current through Register Vol. 49, No. 14, July 15, 2024
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.