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EPA Proposes New Rules on “Forever Chemicals” in Drinking Water

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On March 14, 2023, the U.S. Environmental Protection Agency (“EPA”) announced that it will seek to promulgate new rules for six per- and polyfluoroalkyl substances (“PFAS”), also known as “forever chemicals,” in public water systems under the Safe Drinking Water Act (the “Act”).

Though EPA previously issued a recommended health advisory in 2016 of 70 parts per trillion (“ppt”), this will mark the first time the federal government seeks to curb PFAS in public water systems. The EPA’s proposal is part of a larger push by the Biden Administration to address the use of chemicals that pose severe adverse health impacts. Previous steps include designating two PFAS as “hazardous substances” under the Comprehensive Environmental Response, Compensation, and Liability Act and the distribution of about $10 billion to address these and other emerging chemicals in local communities. The proposed rule significantly reduces the levels for two PFAS types (PFOA and PFOS) from EPA’s prior 2016 health advisory.

Key Elements

The rule seeks to limit six types of PFAS (PFOA, PFOS, PFNA, HFPO-DA, PFHxS, and PFBS) in public water systems. EPA’s treatment of the six varies based on the known and anticipated adverse human health impacts each pose. The key elements of the draft regulations include:

PFOA and PFOS. PFOA and PFOS are treated individually because, according to EPA, the maximum level at which each present no known or anticipated adverse health impacts is so low that EPA expects them to occur well below what current scientific and analytical methods can calculate. As a result, the rule sets limits for PFOA and PFOS using a parts per trillion measurement for each.

Hazard Index for PFNA, PFHxS, PFBS, and HFPO-DA. On the other hand, EPA’s draft rule treats these four PFAS types as a mixture because they are known to often occur together in drinking water, and EPA believes this co-occurrence can result in adverse health impacts. EPA therefore is regulating these substances using a “Hazard Index,” a risk management approach EPA has used previously for regulating chemicals and other toxic materials. A Hazard Index is made up of the sum of each chemical’s Health Based Water Concentration, which in turn is the ratio of the chemical found in the drinking water at which no health effects are expected for that substance. 

Maximum Contaminant Levels. The draft rule sets what are known as Maximum Contaminant Levels (“MCL”) for the six PFAS compounds, which are limits on the amount of a contaminant that can legally be found in drinking water. Pursuant to the Act, EPA has previously set MCLs for other substances, including chlorite, chlorine, arsenic, asbestos, fluoride, lead, mercury, and nitrate. Under the proposed PFAS rule, the MCLs for PFOA and PFOS would each be 4.0 ppt and the MCLs for the PFNA, PFHxS, PFBS, and HFPO-DA mixture would be a Hazard Index of 1.0.

Maximum Contaminant Level Goals. The draft rule also sets non-enforceable public health goals referred to as Maximum Contaminant Level Goals (“MCLG”) for the six PFAS compounds. The MCLGs consider the maximum level of PFAS that can be in drinking water before any known or anticipated adverse health impacts occur. Under the rule, the MCLG for PFOA and PFOS would be zero parts per trillion each and the MCLG for the PFNA, PFHxS, PFBS, and HFPO-DA mixture would be a Hazard Index of 1.0. While the MCLGs are just that—goals—EPA must set the MCLs as close to the MCLGs as possible.


EPA has estimated that the cost to utilities nationwide will be between about $772 million and $1.2 billion annually.


If implemented, EPA’s new rule will significantly impact Massachusetts. The Massachusetts Department of Environmental Protection (“MassDEP”) had, at the time, set some of the strictest PFAS limits in the country in 2020. Under that regulation, public water systems are limited to 20 ppt in aggregate for the six PFAS EPA proposes to regulate in its new rule. As part of its three-year review of the regulation, MassDEP has already stated that it intends to incorporate the lower federal limits proposed under EPA’s draft rule. 

Drinking water utilities will likely incur substantial costs in meeting these new limits.  As just two examples, the Towns of Littleton and Barnstable have already spent about $30 million each to meet the current state PFAS limits.


The proposed MCLs and MCLGs are summarized as follows, along with a comparison to EPA’s 2016 advisory and MassDEP’s current limits (MassDEP):[1]

[1] See 

This advisory was prepared by Matthew Connolly, Matthew Snell, and Daniel Johnston in Nutter’s Real Estate Department. If you would like additional information, please contact any member of our Real Estate Department or your Nutter attorney at 617.439.2000.

This update is for information purposes only and should not be construed as legal advice on any specific facts or circumstances. Under the rules of the Supreme Judicial Court of Massachusetts, this material may be considered as advertising.

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