CSG Law Alert: EPA Proposes to Regulate Six PFAS in Drinking Water

On March 14, 2023, the U.S. Environmental Protection Agency (EPA) announced its proposal for a National Primary Drinking Water Regulation (NPDWR) for six per- and polyfluoroalkyl substances (PFAS), including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), perfluorobutane sulfonic acid (PFBS), and hexafluoropropylene oxide dimer acid (HFPO-DA, also known as GenX chemicals).

The EPA’s proposal includes Maximum Contaminant Level Goals (MCLGs) and Maximum Contaminant Levels (MCLs) for the six PFAS. MCLGs are non-enforceable and represent the level of a contaminant in drinking water below which there is no known or expected risk to health. MCLs, on the other hand, are enforceable drinking water standards and are set as close as possible to MCLGs using the best available treatment technology while taking cost into consideration.

For PFOA and PFOS, the EPA proposed MCLGs of zero and MCLs of 4 parts per trillion (ppt). For PFNA, PFHxS, PFBS, and HFPO-DA, the EPA is proposing a combined hazard index of 1 for both the MCLG and MCL. A hazard index is a measure of the combined potential health risks associated with exposure to multiple hazardous chemicals. It is calculated by adding up the individual hazard quotients for each chemical present and helps assess the risk of adverse health effects from exposure to the mixture of chemicals. This means that the sum of the individual levels of these four PFAS should not exceed 1, as determined by the EPA.

PFAS are synthetic chemicals that have been used in many consumer products since the 1940s, such as non-stick cookware, waterproof clothing, and firefighting foam. They are also used in industrial processes and are known as “forever chemicals” because they do not biodegrade and can accumulate in the environment and living organisms. Numerous studies have found PFAS in the environment, often in areas without identifiable local sources. The chemicals have been linked to health problems, including some cancers, developmental problems in young children, and high cholesterol.

The EPA’s proposed NPDWR for PFAS will have far-reaching impacts for states and public water utilities. New Jersey, one of 21 states that have proposed or adopted limits on PFAS, estimates that three to four times as many utilities will exceed the proposed health limits for PFOA and PFOS under the new rules. As of the date of the EPA’s announcement, 95 New Jersey water systems have incurred at least one violation of the current state health limits for PFAS, according to the New Jersey Department of Environmental Protection (DEP).

If adopted, the EPA’s proposed rule could result in the need for public water utilities to invest in new treatment technologies to remove PFAS from their water supplies, which could be costly. Companies that have manufactured PFAS, such as 3M and DuPont, may also face significant financial liability as lawsuits related to PFAS exposure continue to flood both federal and state courts.

The EPA’s proposed rule underscores the growing concerns about the health and environmental risks associated with PFAS. The EPA determined the proposed MCLGs and MCLs based on the best available science and technology, while also considering the economic impact on public water systems. It is expected that the proposed NPDWR for PFAS will continue to evolve as the EPA considers feedback from stakeholders during the comment period. The EPA has opened a 60-day comment period on the proposed rule, which will allow for public input on the proposed MCLGs and MCLs for the six PFAS.


  1. U.S. Environmental Protection Agency, EPA Proposes National Primary Drinking Water Regulation for PFAS (Mar. 14, 2023), https://www.epa.gov/newsreleases/epa-proposes-national-primary-drinking-water-regulation-pfas.
  2. NJ Spotlight News, Feds propose PFAS limits tighter than NJ’s current restrictions (Mar. 16, 2023), https://www.njspotlightnews.org/2023/03/epa-tightens-limits-on-pfas-chemicals-in-water-pfos-pfoa-pfna/.
  3. Nat’l Conference of State Legislatures, PFAS and Drinking Water: State Actions, https://www.ncsl.org/research/environment-and-natural-resources/pfas-and-drinking-water-state-actions.aspx (last visited Mar. 23, 2023).
  4. Environmental Working Group, PFAS Contamination in the U.S., https://www.ewg.org/research/pfas-contamination-us (last visited Mar. 23, 2023).
  5. Coral Davenport, EPA Proposes Limits on PFAS Chemicals in Drinking Water, N.Y. Times (Mar. 14, 2023), https://www.nytimes.com/2023/03/14/climate/pfas-chemicals-drinking-water.html.

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