- (a) MCL established. The maximum contaminant level (MCL) promulgated under the Safe Drinking Water Act shall be the groundwater protection standard for each Appendix A and C constituent detected in the groundwater.
- (b) MCL not established. If MCL has not been established under the Safe Drinking Water Act for a particular constituent, the background level of the constituent shall be the groundwater protection standard.
(c) Background above MCL. If background level of a particular constituent is above the established MCL, or appropriate health-based levels if no MCL has been established, the background level shall be the groundwater protection standard.
- (1) Published health-based level. For the purposes of this Subsection, the health-based level is a concentration that would result in an increased risk of no greater than 1x 10-5 for carcinogens or a Hazard Index of < 1 for non-carcinogens as calculated by procedures specified in the most recent health-based levels publication by the EPA.
- (2) Health-based level not listed. The DEQ shall be consulted if a health-based level is not listed for a particular constituent.
Added at 20 Ok Reg 1151, eff 6-1-03
Amended at 39 Ok Reg 1074, eff 9-15-22