In the June 26, 2019 Federal Register the Environmental Protection Agency (EPA) published its proposed rule addressing perchlorate in drinking water. EPA proposed a drinking water regulation and a health-based Maximum Contaminant Level Goal (MCLG). The proposed enforceable Maximum Contaminant Level (MCL) and MCLG is 0.056 mg/L (56 µg/L). Public comments will be accepted through July 26, 2019.
In addition to the proposed regulation, EPA requested comments on three alternatives: whether the MCL and MCLG should be set at 0.018 mg/L (18 µg/L); whether the MCL and MCLG should be set at 0.090 mg/L (90 µg/L); or whether instead of issuing a national primary drinking water regulation, EPA should withdraw the 2011 determination to regulate perchlorate in drinking water based on new information that indicates that perchlorate does not appear in public water systems at a frequency and level of public health concern and that there may not be a meaningful opportunity for health risk reduction.
Additionally, EPA listed treatment technologies that would enable water systems to comply with the MCL, including affordable technologies for small systems serving 10,000 persons or less.