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04.03.2023 Legal News

North Carolina Setting for EPA Announcement of Proposal to Limit PFAS in Drinking Water

EPA’s Proposed Rule

Wilmington, North Carolina was the setting for EPA Administrator Michael Regan’s announcement of a new regulatory proposal for so-called “forever chemicals” under the Safe Drinking Water Act (“SDWA”). Following up on a final regulatory determination in March of 2021 to regulate perfluorooctanoic acid (“PFOA”) and perfluorooctane sulfonic acid (“PFOS”) as contaminants under the SDWA, EPA’s most recent action included a preliminary regulatory determination to regulate perfluorohexane sulfonic acid (“PFHxS”), hexafluoropropylene oxide dimer acid (“HFPO-DA”) and its ammonium salt (also known as a GenX chemicals), perfluorononanoic acid (“PFNA”), and perfluorobutane sulfonic acid (“PFBS”), and mixtures of these per- and polyfluorinated substances (“PFAS”) as contaminants under the SDWA. EPA is also proposing a National Primary Drinking Water Regulation (“NPDWR”) and health-based Maximum Contaminant Level Goals (“MCLG”) for these four PFAS and their mixtures as well as for PFOA and PFOS.

EPA is proposing to set the health-based value, or maximum level goal of a contaminant in drinking water at which no known or anticipated adverse effect on the health of persons would occur (the “MCLG”), for PFOA and PFOS at zero. EPA is also proposing enforceable standards that take the form of maximum contaminant levels (“MCLs”) in this proposed regulation. An MCL is the maximum level allowed of a contaminant or a group of contaminants (i.e., mixture of contaminants) in water that is delivered to any user of a public water system (“PWS”). The SDWA generally requires EPA to set an MCL “as close as feasible to” the MCLG. EPA has also included monitoring, reporting, and other requirements to ensure regulated drinking water systems meet the PFAS limits in the regulation.

Considering feasibility, including currently available analytical methods to measure and treat these chemicals in drinking water, EPA is proposing individual MCLs of 4.0 nanograms per liter (ng/L) or parts per trillion (ppt) for PFOA and PFOS. EPA is proposing to use a novel Hazard Index (“HI”) approach to protecting public health from mixtures of PFHxS, HFPO-DA and its ammonium salt, PFNA, and PFBS because of their known and additive toxic effects and occurrence and likely co-occurrence in drinking water. EPA is proposing an HI of 1.0 as the MCLGs for these four PFAS and any mixture containing one or more of them because it represents a level at which no known or anticipated adverse effects on the health of persons is expected to occur and which allows for an adequate margin of safety. EPA says it has determined it is also feasible to set the MCLs for these four PFAS and for a mixture containing one or more of PFHxS, HFPO-DA and its ammonium salt, PFNA, and PFBS as an HI of unitless 1.0.


Proposed MCLG

Proposed MCL 
(enforceable levels)



4.0 parts per trillion
(also expressed as ng/L)



4.0 ppt


1.0 (unitless)

Hazard Index

1.0 (unitless)

Hazard Index



HFPO-DA (commonly referred
to as GenX Chemicals)

The HI is a tool used to evaluate potential health risks from exposure to chemical mixtures. This approach has been used in other EPA programs, such as the Comprehensive Environmental Response, Compensation, and Liability Act (“CERCLA”), but this is the first time it has been used for a drinking water standard. This approach has already drawn criticism, with the American Chemical Council issuing a press release on the same day as the EPA announcement claiming the proposed HI approach contravenes EPA’s own guidance.

According to the American Water Works Association, treating just PFOA and PFOS at the EPA’s proposed levels will cost $3.8 billion a year, based on a study the association commissioned. The association also estimated that 5,000 water systems will need to find new water sources or install treatment technology to meet the new standards, while another 2,500 will need to update their existing technology.

North Carolina DEQ’s PFAS Approach

The North Carolina Department of Environmental Quality (“DEQ”) has been working with public water systems to prepare for the proposed regulation and to assess PFAS levels in drinking water systems across the state. Under the Action Strategy for PFAS, DEQ is taking a whole-of-department approach to protect communities by identifying, reducing, and remediating PFAS pollution. DEQ is also using federal funding under the Bipartisan Infrastructure Law to help address PFAS contamination.

In late 2022, DEQ performed three months of sampling at 50 municipal and county water systems identified in the 2019 PFAST Network study with PFOA/PFOS detections above the minimum reporting level indicated by the 2022 EPA interim health advisories or GenX above 10 ppt. DEQ is actively working with those systems on next steps and providing technical assistance.

Some public water systems in North Carolina are currently monitoring for PFAS voluntarily. DEQ is also implementing plans to sample hundreds of smaller water systems that may not have that capability to better assess the levels of PFAS on a statewide basis. DEQ recommends that public water systems share their PFAS results with customers.

Beyond public water systems, DEQ has taken several actions to better identify PFAS sources and reduce emissions and discharges:

  • Requiring PFAS information from new facilities and industries and developing permit conditions as appropriate throughout the state;
  • Inventorying and prioritizing locations for additional assessment where these substances may have been manufactured, used, discharged, or disposed;
  • Adding permit conditions as appropriate to address PFAS air emissions, waste generation, or wastewater discharges and require disclosure of data and additional monitoring;
  • Conducting groundwater testing and additional monitoring in areas with known or suspected PFAS contamination;
  • Requiring all solid waste sanitary landfills to include PFAS analyses of all regular groundwater, surface water and leachate samples.

Public Participation

EPA is requesting comment on this action, including this proposed NPDWR and MCLGs, and has identified specific areas where public input will be helpful for EPA in developing the final rule. Public comments are due by May 30, 2023. In addition to seeking written input, EPA will be holding a public hearing on May 4, 2023.

PFAS National Primary Drinking Water Regulation Rulemaking-Proposed Rule, 88 Fed. Reg. 18638 (March 29, 2023)