On August 17, 2023, the U.S. Environmental Protection Agency (EPA) released preliminary results from the fifth Unregulated Contaminant Monitoring Rule (UCMR) under Section 1445(a)(2) of the Safe Drinking Water Act (SDWA). The UCMR provides a mechanism for the EPA to collect data regarding impacts to public water systems from “emerging contaminants,” for which the SDWA does not otherwise require sampling and mitigation. The purpose of the UCMR is to allow the agency to collect data regarding the scope and magnitude of impacts to potable water supplies that can serve as the basis for science-based decisions regarding future regulations. Notably, the EPA has indicated that it will interpret the data obtained from the fifth UCMR—or UCMR 5, as it is called—with an eye toward environmental justice.
On March 14, 2023, the EPA proposed a National Primary Drinking Water Regulation under the Safe Drinking Water Act to establish Maximum Contaminant Levels (MCLs) for six per- and polyfluoroalkyl substances (PFAS):
- Perfluorooctanoic acid (PFOA)
- Perfluorooctane sulfonic acid (PFOS)
- Perfluorononanoic acid (PFNA)
- Hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX)
- Perfluorohexane sulfonic acid (PFHxS)
- Perfluorobutane sulfonic acid (PFBS).
The EPA anticipates finalizing the regulation by the end of 2023. Although the science around PFAS is still evolving, the EPA has touted the proposed rule as an essential measure that “will prevent thousands of deaths and reduce tens of thousands of serious PFAS-attributable illnesses.”