On March 14, 2023, the U.S. Environmental Protection Agency (EPA) proposed its long-anticipated National Primary Drinking Water Regulation (NPDWR) to limit six common types of PFAS in drinking water. This is the first time EPA has sought to establish legally enforceable national PFAS contamination levels for drinking water. This step represents the latest action under the Biden administration’s multistep plan to limit PFAS levels in the United States, building upon EPA’s October 2021 PFAS Strategic Roadmap and its pending proposal to designate certain PFAS as hazardous substances under CERCLA, the Comprehensive Environmental Response, Compensation, and Liability Act.
The NPDWR proposes a maximum permitted level of 4 ppt, or parts per trillion, in drinking water for PFOA and PFOS, respectively. It would also limit PFNA, PFHxS, PFBS, and HFPO-DA (commonly referred to as GenX Chemicals) levels to a combined Hazard Index of 1.0. Using the health reference values for each individual chemical (10 ppt for HFPO-DA, 2,000 ppt for PFBS, 10 ppt for PFNA, and 9 ppt for PFHsX), EPA would sum the individual PFAS concentrations across the mixture to yield the Hazard Index result. EPA uses the Hazard Index tool when it believes the sum of hazard quotients for various substances can result in harm to humans.
In addition, the EPA is proposing health-based, nonenforceable Maximum Contaminant Level Goals (MCLGs) for these six PFAS. This represents the level of a contaminant in drinking water below which there is no known or expected risk to health. The EPA proposes MCLGs be set for PFOA at 0, PFOS at 0, and a combined Hazard Index of 1 for PFNA, PFHxS, PFBS, and HFPO-DA. According to the EPA, 4 ppt reflects the lowest concentration that laboratories can currently measure PFOA and PFOS in drinking water.
While the NPDWR is not currently enforceable and does not require any actions until it is finalized, it would require public water systems to monitor water supplies for these six types of PFAS, notify the public if the levels of PFAS surpassed the rule’s enforceable levels, and require providers to reduce the levels of these PFAS in their water supplies if they were to exceed the proposed standards by either treating them or switching to alternative sources of drinking water.
If finalized, this would displace the EPA’s previously recommended health advisory limits. In 2016, the EPA recommended a maximum level of 70 parts per trillion for PFOA and PFOS in drinking water. Then, in June 2022, the EPA issued an interim health advisory for PFOA (0.004 ppt), PFOS (0.02 ppt), GenX Chemicals (10 ppt), and PFBS (2,000 ppt).
Public comment on the proposed regulation will open once the proposed rule is published in the Federal Register. Written comments can be provided at www.regulations.gov under Docket ID: EPA-HQ-OW-2022-0114, and oral comments can be given at a May 4 public hearing. Anyone who would like to provide oral comments must register to do so by April 28. A general overview informational webinar was held on March 16, and a technical overview will be provided on March 29. Additional details can be found here. The EPA expects to finalize the NPDWR by the end of 2023.
PFAS is an umbrella term for a family of thousands of chemicals that have been widely used in manufacturing to make everyday items resistant to extreme temperatures, reduce friction, and repel oil, water, grease, and stains since the 1940s. For more information regarding PFAS and related regulations and litigation, please attend our upcoming continuing legal education on March 30, 2023, or contact members of our PFAS Task Force.
 PFAS stands for per- and polyfluoroalkyl substances
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