EPA Sets Drinking Water Standards for PFAS
Concentrations of six PFAS substances in drinking water will be regulated for the first time under new drinking water standards published by EPA on April 26, 2024.
The final rule sets individual maximum contaminant levels (MCLs) for PFOA and PFOS at 4 parts per trillion (ppt). The agency found no evidence that any level of exposure to either substance is safe, setting aspirational maximum contaminant level goals (MCLGs) of 0 ppt for both.
The final rule also sets individual MCLs (and MCLGs) of 10 ppt for PFHxS, PFNA, and HFPO-DA (known by the trademark GenX). Mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS are subject to a hazard index-based limit.
Public water systems are required to conduct initial monitoring by April 2027, be compliant with the MCLs by April 2029, and conduct regular compliance monitoring. Water systems must include detected PFAS in their annual reports and notify the public if a MCL violation has been detected.
EPA characterizes the regulation as flexible. The final rule allows reductions in initial monitoring for most small water systems, using previously collected drinking water data to satisfy initial monitoring requirements, and reduced compliance monitoring based on sampling results. Additionally, the final rule does not dictate how PFAS be removed.
In a press release, EPA said it expects that approximately 6-10% of water systems subject to the final rule may need to take action to meet the standards, reducing PFAS exposure for around 100 million Americans.
A previous Verdant Law blog post on the proposed drinking water standards can be found here.