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April 11, 2024

EPA Issues Enforceable Limits for PFAS in Drinking Water

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On April 10, 2024, the Environmental Protection Agency (“EPA”) announced the final National Primary Drinking Water Regulation (the “Regulation”) for six per- and polyfluoroalkyl substances (“PFAS”) that may be present in drinking water. PFAS are known as “forever chemicals” due to their resistance to degradation in the environment when exposed to heat, cold, acidity, and traditional solvents—resulting in a long half-life. PFAS are pervasive. Products incorporating PFAS include nonstick cookware, waterproof textiles, medical devices, clothing, electronics and food packaging. Historically, PFAS were used in numerous manufacturing processes and products that are now subject to an ever-broadening array of state and federal regulation.

Application of the Regulation

The EPA’s final Regulation sets legally enforceable levels, called Maximum Contaminant Levels (“MCLs”) for five individual PFAS in drinking water. The EPA set enforceable 4 parts per trillion MCLs for PFOA and PFOS. These were the same levels proposed in last year’s proposed Regulation. The EPA also finalized enforceable levels of 10 parts per trillion for three other PFAS: (i) PFNA, (ii) PFHxS and (iii) HFPO-DA (commonly called GenX Chemicals). These three chemicals had not been designated for individual regulation under the 2023 proposed Regulation. In any event, the proposed MCLs remain miniscule; one part per trillion is equivalent to a single drop of water in twenty Olympic-sized swimming pools.

On top of individual contaminant levels, the EPA used a Hazard Index MCL to regulate co-occurring or combined levels of PFNA, PFHxS, HFPO-DA and Perfluorobutane sulfonic acid (PFBS). A Hazard Index is a method for measuring the dose-additive effects of a mixture of substances that may synergize to cause worsened health outcomes.

The EPA noted that the reason for setting these particular MCLs is that they are the lowest levels that are both detectable and achievable for public water systems, despite scientific disagreement as to the harmful level of PFAS over background exposure (and the potential health consequences of exposures at different levels). The EPA also set non-enforceable maximum contaminant level goals (MCLGs) aiming for the complete elimination of PFOA and PFOS from drinking water.

 Regulated PFAS Chemical MCL   MCLG
 PFOA (perfluorooctanoic acid)  4 ppt 0 ppt 
 PFOS (perflouorooctane sulfonic acid)  4 ppt  0 ppt
 PFNA (perfluorononanoic acid)  10 ppt  10 ppt
 PFHxS (perfluorohexane sulfonic acid)  10 ppt  10 ppt
 HFPO-DA, or GenX Chemicals (hexafluoropropylene oxide dimer acid)  10 ppt  10 ppt
 Mixture of PFNA, PFHxS, HFPO-DA, and PFBS (perfluorobutane sulfonic acid)  Hazard Index 1  Hazard Index 1


Enforcement Timeline

The new Regulation will go into effect sixty days after it is published in the Federal Register. Public water systems will have until 2027 to establish PFAS monitoring programs and provide the public with information about the level of these PFAS in the drinking water. If monitoring reveals drinking water PFAS levels in excess of the MCLs, public water systems will have until 2029 to implement solutions to meet the MCLs established by the Regulation. If PFAS drinking water levels are not addressed by 2029, public water systems will have violated the new MCLs and must inform the public of the violation.

Implications of the Regulation

The EPA evaluated the costs of compliance with the Regulation at $1.5 billion per year, while the potential annual health benefits evaluated by the EPA slightly exceeded those costs. Along with the final version of the Regulation, the EPA has made a number of fact sheets and FAQs available on its website and has scheduled several webinars for affected entities over the next several weeks. 

The American Chemistry Council (“ACC”) raised concerns about the new Regulation, citing studies estimating that the cost of compliance will exceed $4 billion per year. The ACC also argued that the Regulation’s MCLs are based on outdated science and are therefore overinclusive, imposing costs on many more public water systems than the science would support. 

Regulatory Aftermath

The EPA’s new Regulation is just the latest in a broad regulatory effort at the federal, state, and local level designed to reduce the use of PFAS chemicals in commerce and remediate PFAS already found in products and the environment. These efforts range from disclosure requirements under the Toxic Substances Control Act to outright bans on the use or import of PFAS in certain applications in states like Maine, Vermont, Minnesota and California. It is likely that the new Regulation will result in additional regulation and enforcement actions at the state and local level and could lead to additional litigation over PFAS presence in drinking water.

When the EPA announced the final Regulation, it announced an initial $1 billion in funding to help localities implement the final regulation, with other funding potentially available later. However, with over 66,000 public drinking water systems subject to the Regulation, that funding almost certainly will not cover all costs of monitoring and implementing solutions to PFAS levels. In the end, unless an alternative source of funding is located, water customers will likely see an increase to their monthly water bills.

Additionally, the Regulation’s MCLs will likely lead to increased litigation between third parties over responsibility for monitoring and transition costs. It is unclear whether the Regulation provides answers for the currently-pending litigation. But concerns that the EPA’s regulatory standards will be imported into current or future litigation—despite conflicting evidence to support the particular MCLs proposed by EPA—have been prevalent since the proposed Regulation was issued in March 2023.

It is reasonably likely that litigation over the new Regulation will follow, given the breadth of the current and potential claims related to PFAS exposure. It is too early to speculate as to what, if anything, will survive to implementation. However, we will monitor the ongoing regulatory and legal proceedings and provide updates as appropriate.