By the Numbers: EPA’s Proposal to Regulate 6 PFAS Chemicals From Drinking Water

EPA estimates that the proposal would result in $777 million–$1.211 billion in total annualized costs, with $30–$61 million in additional annual costs for public water systems (“PWSs”) if EPA lists PFAS as hazardous wastes under the Resource Conservation and Recovery Act (“RCRA”) and establishes hazardous waste disposal requirements for PFAS-contaminated drinking water treatment residuals and wastes.  And these direct costs may be only the beginning ⸻ the rule has the potential to be precedent-setting for other PFAS compounds in future drinking water regulations. Members of the public interested in commenting have until May 30, 2023, to submit comments on the proposed rule.

Below, we break down EPA’s proposal by the numbers.

For more background on PFAS chemicals, please see our prior posts.

9,000+ PFAS chemicals that have been used worldwide in commercial household products, industrial products, construction materials, and many other sources since the 1940s. PFAS compounds have properties that make them highly stable and resistant to degradation in the environment and are therefore colloquially called “forever chemicals.” But while they share certain similarities, each substance has its own unique characteristics and historic uses.

6 PFAS chemicals EPA has proposed to regulate in drinking water. They are:

• Perfluorooctane sulfonic acid (“PFOS”);
• Perfluorooctanoic acid (“PFOA”);
• Perfluorohexane sulfonic acid (“PFHxS”);
• Hexafluoropropylene oxide dimer acid (“HFPO-DA”) and its ammonium salt (collectively, “GenX chemicals”);
• Perfluorononanoic acid (“PFNA”); and
• Perfluorobutane sulfonic acid (“PFBS”)

PFOS and PFOA are the two most widely studied PFAS. In March 2021, EPA finalized a regulatory determination to regulate PFOS and PFOA under the SDWA based on EPA’s findings about their long-term health consequences, occurrence in drinking water,² and the opportunities to reduce health risks. The other four PFAS chemicals are less well-studied, but EPA has stated in its proposal that there is enough information to regulate them based on their adverse health effects and occurrences in drinking water.

29 PFAS about which EPA is collecting occurrence data under the fifth Unregulated Contaminant Monitoring Rule (“UCMR 5”). The SDWA requires that once every five years, EPA publish a list of unregulated contaminants to be monitored by PWSs for evaluation and consideration in future regulatory actions. The proposed rule suggests PWSs may be able to comply with initial monitoring requirements using data collected during UCMR 5.

2 types of entities subject to this regulation if finalized: (1) PWSs, specifically community water systems (“CWSs”) and non-transient, non-community water systems (“NTNCWs”),³ and (2) “primacy agencies” that oversee PWSs.⁴ According to the proposed rule, 49,193 CWSs and 17,337 NTNCWs will be subject to the regulation when finalized. Most states and U.S. territories have primacy overseeing PWSs in their states ⸻ the exceptions are Wyoming and the District of Columbia, where EPA serves as the primacy agency.

66,530 PWSs EPA estimates would be subject to the regulation if finalized.

0 parts per trillion (“ppt”) as the proposed maximum contaminant level goal (“MCLG”) for PFOA and PFAS. The MCLG is the level at which no known or anticipated adverse effects on the health of persons occurs, allowing an adequate margin of safety. MCLGs are purely health-based and non-enforceable. When EPA determines that a regulated contaminant is carcinogenic to humans, as a matter of policy, the agency sets the MCLG at zero.

4 ppt as the proposed maximum contaminant level (“MCL”) of PFOA and PFAS in PWSs. The MCL is an enforceable standard and must be set as close to the MCLG as is feasible. Feasibility considers currently available analytical methods to measure and treat these chemicals in drinking water. The SDWA allows the EPA Administrator to weigh the benefits and costs of a rule when setting an MCL.

The proposed 4 ppt MCL for PFOA and PFAS is notably lower than the limits set by states that already regulate these chemicals. For example, New York limits the concentrations of PFOA and PFOS at 10 ppt; Michigan at 16 ppt for PFOS and 8 ppt for PFOA; and Washington State at 15 ppt for PFOS and 10 ppt for PFOA. Thus, even in those states that have regulated PFOA and PFAS, a more stringent federal standard will likely require PWSs to incur additional compliance costs, which may then be passed on to their customers.

1.3 ppt as the proposed “trigger” level for reduced monitoring requirements of PFOA and PFOS. The rule proposes that PWSs must conduct initial monitoring and ongoing compliance monitoring for the PFAS identified in the proposal. If PWSs can demonstrate that PFAS concentrations in drinking water are below one-third of the MCLs (i.e., 1.3 ppt for PFOA and PFOS), then they are eligible for reduced monitoring.

1.0+ hazard index level for a mixture of four PFAS (PFHxS, HFPO-DA, PFNA, and PFBS). Unlike PFOA and PFAS, which EPA has proposed to regulate on an individual contaminant basis, EPA has proposed to regulate these four PFAS as a mixture. This is the first time a hazard index level has been applied in a regulation under the SDWA. The hazard index level is based on dividing observed drinking water concentrations by a value at which EPA does not anticipate adverse effects for each of the four PFAS chemicals and summing those values. The sum of the individual values is evaluated relative to 1.0 based on a rolling annual average (“RAA”) drawing on compliance monitoring data. When that RAA is >1.0 (normal rounding and significant digit rules apply), the proposed rule would provide that a violation of the drinking water regulation has occurred, and PWSs must take actions to remedy the situation. EPA has indicated that it is developing a calculator to assist PWSs in determining the hazard index from collected samples. Furthermore, EPA has proposed that a hazard index of 0.33 will serve as the trigger level for PWSs to be eligible for reduced monitoring associated with these four PFAS.

3 treatment technologies EPA has determined are available for PWSs to use to remove PFAS in drinking water. Under the proposed rule, PWSs with PFAS levels that exceed the proposed MCLs must take certain actions to address the MCL exceedance. These actions generally include the installation and operation of treatment technologies that meet certain criteria such as cost and efficiency. In the proposed rule, EPA has proposed three types of treatment technologies PWSs can install to remove PFAS from drinking water: (1) granular activated carbon; (2) anion exchange; and (3) high-pressure membrane technologies.⁵ Non-treatment options, such as replacing a drinking water source or purchasing water from another water system, are also available as compliance tools.

3,400–6,300 PWSs that EPA anticipates will exceed one or more MCLs in this proposed rule and that will have to apply treatment technologies or seek other non-treatment options.

$777 million–$1.211 billion in total annualized costs for PWSs to comply with the proposed rule, depending on the discount rate applied. This annualized cost estimate considers sampling, implementation and administration, and treatment costs for PWSs once the rule goes into effect. EPA has also estimated the public health benefits of this proposed rule and believes that the estimated benefits outweigh the estimated costs.

$30–$61 million in additional costs per year for PWSs if EPA decides to regulate PFAS as hazardous wastes under RCRA.

60 days for public comment from March 29, the date EPA published the proposed rule in the Federal Register.

8–9 months until the end of 2023, which is the timeframe EPA has said it intends to use to issue a final rule.

3 years for PWSs to be in compliance with the new regulations once EPA finalizes the proposed rule.

If EPA finalizes this rule, PWSs and primacy agencies will face challenges in implementing these requirements, particularly if EPA finalizes the 4 ppt MCLs for PFOA and PFOS. As noted above, these proposed MCLs are more stringent than any state regulation to date. Any final rule may also be challenged under the SDWA or Administrative Procedure Act depending on how EPA incorporates and responds to public comments in the final rule.

The PFAS Taskforce

V&E’s PFAS Taskforce is dedicated to helping our clients navigate the emerging and complex law and regulations that may be used to address PFAS and related chemicals. By actively tracking and analyzing the different federal and state regulatory approaches to addressing PFAS — whether in water, groundwater, soil, and air — and engaging with the evolving scientific understanding of PFAS substances, we can help our clients build short- and long-term strategies to address potential liability, remediation, and litigation concerns regarding these emerging contaminants. Drawing upon the significant capabilities in our cross-office environmental team, V&E’s PFAS Taskforce is on hand to provide practical and tailored guidance for our clients as they prepare for the shifting PFAS landscape.

¹ In 1998, EPA added contaminants to a primary drinking water regulation in the Stage 1 Disinfectants and Disinfection Byproducts Rule. In 2011, EPA determined that it should regulate perchlorate in a primary drinking water regulation but the agency withdrew that regulatory determination in 2020. 

² PWSs provide water for human consumption through pipes or other constructed conveyances to at least 15 service connections or regularly serves least 25 people. These systems may be privately or publicly owned.

³ An NTNCWS regularly supplies water to at least 25 of the same people at least six months per year (e.g., a school, factory, etc.).

⁴ A primacy agency is an administrative agency with primary responsibility for implementing the SDWA. A CWS supplies water to the same population year-round.

⁵ Each of these technologies is a separation process to separate contaminants from water through chemical processes. Granular activated carbon separates contaminants like PFAS from drinking water using carbon-based materials; anion exchange uses resin, and as drinking water moves through the resin, an anion of PFAS exchanges for an anion on the resin; and high-pressure membrane processes force water through a membrane at greater than osmotic pressure, which results in water with few solutes (i.e., contaminants) left in it.