26.04.01.13-2

.13-2 General Monitoring and Compliance Requirements for Radionuclides.

A. This regulation applies to a community water system (CWS). The Approving Authority may require more frequent monitoring than specified in Regulations .13 and .13-1 of this chapter, or may require confirmation samples at its discretion. The results of the initial and confirmation samples shall be averaged for use in compliance determinations.

B. Suppliers of water shall monitor at the time designated by the Approving Authority during each compliance period.

C. Compliance with Regulation .09 of this chapter shall be determined based on the analytical results obtained at each sampling point. If one sampling point is in violation of an MCL, the system is in violation of the MCL.

D. For a CWS monitoring more than once per year:

(1) Compliance with the MCL is determined by a running annual average at each sampling point;

(2) If the average of any sampling point is greater than the MCL, the system is out of compliance with the MCL; and

(3) If any sample result causes the running average to exceed the MCL at any sample point, the system is out of compliance with the MCL immediately.

E. Suppliers of water shall include all samples taken and analyzed under the provisions of Regulations .13, .13-1, and .13-2 of this chapter in determining compliance, even if that number is greater than the minimum required.

F. If a supplier of water does not collect all required samples when compliance is based on a running annual average of quarterly samples, compliance shall be based on the running average of the samples collected.

G. If a sample result is less than the detection limit, zero will be used to calculate the annual average, unless a gross alpha particle activity is being used instead of radium-226, uranium, or both. If gross alpha particle activity is being used instead of radium-226, uranium, or both and if the gross alpha particle activity result is less than detection, 1/2 the detection limit shall be used to calculate the annual average.

H. The Approving Authority may delete results of obvious sampling or analytical errors.

I. If the MCL for radioactivity set forth in Regulation .09 of this chapter is exceeded, the operator of a CWS shall give notice to the Approving Authority as required by Regulation .19 of this chapter and to the public as required by Regulation .20 of this chapter.

J. Suppliers of water may be eligible for variances or exemptions from the maximum contaminant levels for radionuclides based on criteria outlined in 40 CFR §142.65.