In the absence of an enforceable federal drinking water standard for per- and polyfluoroalkyl substances (“PFAS”), many states have started regulating PFAS compounds in drinking water. The result is a patchwork of regulations and standards of varying levels, which presents significant operational and compliance challenges to impacted industries. This client alert surveys the maximum contaminant levels (“MCLs”), as well as guidance and notification levels, for PFAS compounds – typically perfluorooctane sulfonate (“PFOS”) and perfluorooctanoic acid (”PFOA”) – in drinking water across the United States.
I. Federal Actions
There are two significant actions that the Federal Government has taken to establish requirements for certain PFAS substances.
A. Maximum Contaminant Levels
According to the PFAS Strategic Roadmap, EPA originally planned to issue proposed MCLs for PFOA and PFOS in drinking water by the end of 2022. Recently, EPA announced that the proposed listing will be released in March 2023, and the final regulation should be issued in September 2024, if not sooner.
This action will result in enforceable national drinking water standards for two PFAS compounds. A national drinking water limit will require drinking water systems across the entire country to evaluate the concentration of these two compounds in drinking water, and to implement treatment systems and permit limits to achieve the MCLs.
B. Health Advisory Levels
On June 15, 2022, the United States Environmental Protection Agency (“EPA”) issued four proposed health advisories (“HAs"). The values are as follows:
The newly issued HAs for PFOA and PFOS supersede and dramatically reduce EPA’s 2016 Drinking Water Health Advisory Level of 70 ppt for PFOS and PFOA
EPA's HAs are non-enforceable, but are intended to provide technical information to state agencies and other public health officials regarding health effects, analytical methodologies, and treatment technologies associated with drinking water PFAS contamination.
For additional information, please refer to BCLP’s Client Alert regarding the new HA levels.
II. State Regulations
Until the federal government enacts final MCLs for PFOA and PFOS, the regulatory landscape for PFAS compounds in drinking water consists of an array of widely varying state-promulgated standards and regulations. For example, concentrations range from 3 ppt (California; PFHxA only) to 667,000 ppt (Nevada; PFBS only), depending on the PFAS compounds, the nature of the regulation, and the state’s view on which levels may result in health effects. The chart below illustrates the significance of the discrepancies between the regulatory levels for PFOA and/or PFOS.

The map and chart is current as of February 13, 2023, but this is a very active regulatory space, and significant state action is anticipated in 2023. For example, Delaware, Maine, Rhode Island, and Virginia have enacted legislation to establish MCLs for PFAS compounds for drinking water, so implementing regulations in those jurisdictions may be forthcoming. Additionally, numerous states, including Kentucky, have proposed, but not yet promulgated, drinking water regulations for PFAS.
Moreover, the New York Department of Health (“DOH”) proposed 10 ppt MCLs for four PFAS substances (PFDA, PFNA, PFHxS and PFHpA), along with a combined or aggregate MCL of 30 ppt for six PFAS substances (PFOA, PFOS, PFDA, PFNA, PFHxS and PFHpA).
Additionally, on November 15, 2022, a Michigan court invalidated that state’s seven PFAS drinking water MCLs, finding that the agency had not adequately explained its analysis of the cost impacts of the proposed law in the regulatory impact statement. The Michigan PFAS MCLs will remain in effect until the court issues a final judgment, but the decision highlights the tension between the regulatory intent and the resulting cost, and further litigation is expected as more states – and eventually the federal government - enact similar legislation.
No PFAS drinking water regulations (as of the date of publication):
Alabama, Arizona, Arkansas, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Montana, Nebraska, North Dakota, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, and Wyoming
Key:
III. How Do These Limits Impact Businesses?
MCLs set the maximum concentration of a given contaminant that can be present in drinking water. Drinking water systems are ultimately responsible for meeting the applicable MCLs and are required to ensure that drinking water distributed to the public meets these limits. State agencies often include discharge limits for drinking water sources to ensure that the drinking water provider can comply with the MCLs.
Businesses that currently or historically have used PFAS compounds, or have reason to believe that they may be present in their process wastewater effluent, should evaluate the following considerations:
- Whether their wastewater discharges, either directly or following treatment by the POTW or other treatment facilities, are eventually released to sources that are used for drinking water;
- Whether their discharge contains any of the PFAS compounds that are regulated in their jurisdiction; and
- Whether they are likely to be subject to permit conditions limiting the allowable concentration of PFAS compounds in their wastewater discharges.
Acquiring this information will allow businesses to determine whether they need to modify their operations to reduce or eliminate PFAS from their waste stream to achieve compliance with an existing standard, or in anticipation of likely future permit conditions.
IV. Conclusion
The regulation of PFAS substances in drinking water will continue to develop over the next several years as additional research is conducted on potential health impacts, and as regulators at both the federal and state levels develop a deeper understanding of the prevalence of PFAS compounds in drinking water and the efficacy of different MCLs.
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