U.S. EPA Grows More Aggressive on Forever Chemicals (PFAS) in Drinking Water

After years of non-enforceable and nonbinding health advisories for per- and polyfluoroalkyl substances (PFAS), also called “forever chemicals”, the U.S. Environmental Protection Agency (EPA) on March 14, 2023, moved aggressively by announcing its first-ever proposed rule for PFAS National Primary Drinking Water Regulations. If promulgated, the rule will create legally enforceable drinking water standards to protect public health by limiting PFAS levels in public drinking water. This proposed rule seeks to set enforceable Maximum Contamination Levels (MCLs) for six PFAS types, which will limit the maximum permissible level of PFAS contaminants in public water systems.

With this rule, EPA continues to advance its comprehensive PFAS strategy provided in its 2021-2024 PFAS Strategic Roadmap.

PFAS – The Ubiquitous Forever Chemicals

PFAS are a class of synthetic chemicals used in numerous industries and consumer products for their non-stick, stain-resistant, and water-resistant qualities, amongst others. PFAS are referred to as “forever chemicals” due to their innate chemical stability, which prevents natural degradation and allows persistent accumulation in the environment and living organisms.

Since their initial use in industry and consumer products in the 1940s, significant PFAS contamination and accumulation have been identified in surface water, groundwater, soil, and air in both rural and urban areas across the United Stated and the globe. Many industries rely on PFAS as part of their manufacturing process, which includes industries such as: plastics, synthetic fiber manufacturing; metal finishing; pulp, paper, and paperboard manufacturing; textile mills; and commercial airport fire suppression systems.

To date, PFAS contamination has been associated with a wide array of human health issues including liver and kidney toxicity, immune system defects, hematological effects, reproductive and developmental effects, and cancer. 

The Proposed Rule & Future Implications

Under the proposed rule, new MCLs for six PFA types1, and mixtures thereof, will be created with the goal of limiting the amount of such PFAS in drinking water sources. For PFOA and PFOS, which are used to manufacture a wide array of consumer goods, the EPA is proposing an MCL of 4.0 parts per trillion which is the lowest concentration that many commercial labs can detect. For the remaining four PFAS types, EPA is using a Hazard Index which will evaluate those substances as a mixture as they appear in drinking water, rather than using chemical-by-chemical standards.2

As the first-ever PFAS National Primary Drinking Water Regulation, the proposed PFAS rule will preempt state and local rules governing PFAS. States may promulgate their own PFAS-related drinking water regulations, but such rules must be no less stringent than the PFAS National Primary Drinking Water Regulation. States seeking to obtain or retain enforcement responsibility under the federal Safe Drinking Water Act for PFAS will either have to promulgate new regulations or revise existing regulations to align with the final PFAS National Primary Drinking Water Regulation.

If the new PFAS rule is promulgated, public water systems will be required to monitor for certain PFAS, notify the public when levels exceed an MCL, and take action to reduce the levels of such PFAS. This will impact industries that rely on these PFAS as part of their manufacturing process and their downstream public water systems. 

Presently, EPA calculates that it will cost approximately $772 million nationally for public water systems to achieved compliance with the proposed rule. However, it is important to note that amount does not account for private sector costs of compliance for monitoring, reporting, and reductions of PFAS in water effluent discharge. Public water systems seeking to achieve compliance with the new PFAS rule will look upstream to industrial dischargers who will be forced to share in the costs of compliance.

As of the date of this alert, the proposed rule is open to public comment, and comments must be received on or before May 30, 2023. EPA will be holding a public hearing on the proposed PFAS National Primary Drinking Water Regulation Rulemaking on May 4, 2023.


If your business presently relies on PFAS for manufacturing or other purposes, we suggest you stay up-to-date as the proposed rule advances to codification. Industrial dischargers will likely feel the impact of the final regulation as public water systems will be monitoring for certain PFAS and reductions in PFAS in effluent will likely be required. Finally, with EPA taking more aggressive action on PFAS, state agencies will likely do the same, and many state agencies have already started doing so.

If you would like assistance with understanding the impact or requirements of the newly proposed PFAS rule, or have any questions about the ongoing rule-making process, please contact Pam Barker.

1Regulated PFAS types under the proposed rule include: perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX Chemicals), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS).

2For PFNA, HFPO-DA, PFHxS, and PFBS, the proposed rule treats these PFAS as a mixture and calculates compliance based on a Hazard Index which combines ratios for each of the four PFAS types. If the combined four ratios of these PFAS types is at or above 1.0, then the public water system will be required to reduce levels until the Hazard Index is below 1.0.  It is possible for a single one of these PFAS types to exceed the Hazard Index requiring reductions upstream.