Minnesota systems are unlikely to be affected.

The following article was posted in the Winter 2019-2020 edition of Waterline, a quarterly newsletter related to public water systems in Minnesota published by the Minnesota Department of Health’s Drinking Water Protection Program.

“The U. S. Environmental Protection Agency (EPA) is proposing a maximum contaminant level (MCL) and MCL goal (MCLG) for perchlorate of 0.056 parts per million (ppm). Perchlorate is a chemical compound from commercially produced sales. The EPA has been studying perchlorate because of potential contamination to water, which can reduce hormone production in the thyroid gland.

The EPA is proposing requirements for water systems to conduct monitoring and reporting for perchlorate and to provide information about perchlorate to their consumers through public notification and consumer confidence reports. It includes a list of treatment technologies that would enable water systems to comply with the MCL, including affordable compliance technologies for small systems serving 10,000 persons or fewer.

The EPA is also considering and has sought public comments on instead setting the MCL and MCLG at 0.018 ppm or at 0.090 ppm.

Another alternative is to not regulate perchlorate in drinking water based on new information that perchlorate does not occur in public water systems with a frequency and at levels of public-health concern.

The Minnesota Department of Health tested some community water systems in the state under the first Unregulated Contaminant Monitoring Rule in the early 2000s; it found no detections over 0.018 ppm. As a result, the department does not anticipate many, if any, MCL violations among public water systems in the state, even if a standard is adopted.”

You can view the whole newsletter and/or subscribe to The Waterline here.