Insights
PFAS drinking water standards: state-by-state regulations
Updated: January 2026
Jan 19, 2026Summary
The regulation of per- and polyfluoroalkyl compounds (“PFAS”) in drinking water remains an ever-evolving area for both federal and state legislatures and agencies. With respect to actions at the federal level, in May 2025, the United States Environmental Protection Agency (“EPA”) affirmed Maximum Contaminant Levels (“MCLs”) of 4 parts per trillion (“ppt”) for two PFAS compounds, perfluorooctanoic acid (“PFOA”) and perfluorooctane sulfonic acid (“PFOS”). With respect to actions at the state level, many states have regulated the presence of PFAS compounds in drinking water, but have done so in a variety of different ways and at different levels resulting in a patchwork of regulations and standards.
This BCLP Insight surveys the drinking water regulations, as well as other guidance and notification levels, for PFAS compounds in drinking water across the United States.
Federal Actions
As discussed in BCLP’s May 15, 2025 Insight, EPA announced that it would issue a proposed rule in fall 2025 to implement several changes to the MCLs previously issued by EPA for drinking water in April 2024. To date, the proposed PFAS drinking water rule has not been issued.
Based upon interim announcements by EPA, the following summarizes much of the anticipated proposed rulemaking and other EPA actions:
- The existing 4 ppt MCLs for PFOA and PFOS are anticipated to remain in place.
- The MCLs for three other PFAS – PFHxS, PFNA, and HFPO-DA along with the one Hazard index for combinations of these compounds and PFBS -- are anticipated to be rescinded and possibly reconsidered.
- The agency expects to establish a new technical assistance and outreach initiative for public water systems (in addition to continuing to offer the water technical assistance (WaterTA) service). EPA stated that the new initiative, known as the PFAS OUTreach Initiative, or PFAS OUT, would prioritize outreach to public water systems in need of capital improvements to address PFAS impacts and will connect those utilities with “resources, tools, funding, and technical assistance” to position the utilities to achieve compliance with the MCLs for two specific compounds: PFOA and PFOS.
In addition to the actions outlined above, there is an active, pending federal lawsuit styled American Water Works Association v. EPA before the Court of Appeals for the D. C. Circuit. Two petitioner water utility entities challenged EPA’s 2024 rulemaking establishing MCLs for certain PFAS compounds (“EPA’s 2024 Rule”) arguing, among other things, that “EPA did not rely on the best available science and the most recent occurrence data.” On September 11, 2025, following the change in federal administrations, EPA moved to vacate portions of EPA’s 2024 Rule through the litigation, consistent with the anticipated rulemaking originally announced for fall 2025. This lawsuit may ultimately determine whether the MCLs for PFOA and PFOS will take or remain in effect.
For additional information, please refer to EPA’s NPDWR April 2024 website and EPA’s NPDWR Implementation website.
State Regulations
The state-level regulatory landscape for the presence of PFAS compounds in drinking water is currently an array of widely varying standards and regulations. For example, regulatory concentration limits range from 0.00266 ppt (Nevada; PFOA only) to 400,000 ppt (Michigan; PFHxA only), depending on factors such as the PFAS compound at issue and the nature of the regulation. To illustrate these differences, the graph below depicts the discrepancies between current state regulatory levels for PFOA and/or PFOS.
Similarly, the map below reflects the current status of state-level regulations nationwide as of January 2, 2026. As with any active regulatory space, additional state action is anticipated on a rolling basis.
Of these anticipated developments, Florida, Illinois, and Virginia have enacted legislation to establish MCLs and/or statewide target levels for PFAS compounds in drinking water. Additionally, several states, including Arizona, California, Georgia, Idaho, and South Carolina, have proposed, but not yet promulgated, various types of drinking water requirements for PFAS. Notably, several states, including California, Georgia, New York, Pennsylvania, Vermont, Washington, and Wisconsin are proposing MCLs and other restrictions that, in part, adopt certain concentration values in EPA’s 2024 Rule.
Water systems may also be subject to sampling requirements, which are not discussed in this alert. For example, several states impose the sampling protocol or testing requirements on Public Water Systems (“PWS”) or Community Water Systems (“CWS”). Some states, such as Illinois, have notified numerous CWS of sampling results that have identified certain PFAS constituents in groundwater.
States that have adopted a standard lower than 70 ppt |
Concentration level
3 ppt (stated by the California Water Boards as 3 ng/L)
Chemical(s) and type of regulation
PFHxS (Notification)
Regulatory information
Regulation and related information
Concentration level
4 ppt (stated by the California Water Boards as 4 ng/L)
Chemical(s) and type of regulation
PFOA (Notification)
Regulatory information
Regulation and Related Information
Concentration level
4 ppt (stated by the California Water Boards as 4 ng/L)
Chemical(s) and type of regulation
PFOS (Notification)
Regulatory information
Concentration level
2 ppt
Chemical(s) and type of regulation
6:2 chloropolyfluoroether sulfonic acid (Notification)
Regulatory information
Action Level and related information
Concentration level
5 ppt
Chemical(s) and type of regulation
8:2 chloropolyfluoroether sulfonic acid (Notification)
Regulatory information
Action Level and related information
Concentration level
10 ppt
Chemical(s) and type of regulation
PFOS (Notification)
Regulatory information
Action Level and related information
Concentration level
12 ppt
Chemical(s) and type of regulation
PFNA (Notification)
Regulatory information
Action Level and related information
Concentration level
16 ppt
Chemical(s) and type of regulation
PFOA (Notification)
Regulatory information
Action Level and related information
Concentration level
19 ppt
Chemical(s) and type of regulation
Gen X or HFPO-DA (Notification)
Regulatory information
Action Level and related information
Concentration level
49 ppt
Chemical(s) and type of regulation
PFHxS (Notification)
Regulatory information
Concentration level
4 ppt
Chemical(s) and type of regulation
PFOS and PFOA (Forthcoming MCLs)
Regulatory information
Implementation Plan and Related Information
Concentration level
10 ppt
Chemical(s) and type of regulation
PFHxS, PFNA, and Gen X (Forthcoming MCLs)
Regulatory information
Concentration level
4 ppt, etc.[1](stated by the Hawaii Department of Health as 0.004 µg/L)
Chemical(s) and type of regulation
PFOS, PFOA, and 24 other PFAS compounds (Guidance)
Regulatory information
Environmental Action Levels (Table A) and Related Information
[1] Hawaii regulates 24 additional PFAS compounds, including the following: PFDA (7.7 ppt); PFNA, PFHxS, and HFPO-DA (10 ppt); PFUnDA (19 ppt); PFDoDA and PFTrDA (26 ppt); PFHpS and PFDS (38 ppt); PFOSA (46 ppt); PFHpA (77 ppt); PFTeDA (260 ppt); PFPrA (510 ppt); PFPeS (580 ppt); ADONA (1,200 ppt); PFPeA and 6:2 FTS (1,500 ppt); PFHxA and 6:2 FTTAoS (1,900 ppt); PFBS (2,000 ppt); 8:2 FTOH (4,200 ppt); 6:2 FTOH (5,000 ppt); PFBA (15,000 ppt); and PFEtA (18,000 ppt).
Concentration level
4 ppt (stated by the Illinois Environmental Pollution Control Agency as 4 ng/L)
Chemical(s) and type of regulation
PFOA (Guidance)
Regulatory information
Regulation and related information
Concentration level
4 ppt (stated by the Illinois Environmental Pollution Control Agency as 4 ng/L)
Chemical(s) and type of regulation
PFOS (Guidance)
Regulatory information
Regulation and related information
Concentration level
10 ppt (stated by the Illinois Environmental Pollution Control Agency as 10 ng/L)
Chemical(s) and type of regulation
PFNA (Guidance)
Regulatory information
Regulation and related information
Concentration level
10 ppt (stated by the Illinois Environmental Pollution Control Agency as 10 ng/L)
Chemical(s) and type of regulation
HFPO-DA (Guidance)
Regulatory information
Regulation and Related Information
Concentration level
10 ppt (stated by the Illinois Environmental Pollution Control Agency as 10 ng/L)
Chemical(s) and type of regulation
PFHxS (Guidance)
Regulatory information
Regulation and related information
Concentration level
20 ppt (stated in the Interim Drinking Water Standard as 20 ng/L)
Chemical(s) and type of regulation
6 PFAS substances combined: PFOA, PFOS, PFHxS, PFNA, PFHpA, and PFDA (Notification)
Regulatory information
Interim Drinking Water Standard, 2024 Maine PFAS Drinking Water Report, and Related Information
Concentration level
20 ppt (stated in the regulation as 20 ng/L)
Chemical(s) and type of regulation
6 PFAS substances combined: PFOA, PFOS, PFHxS, PFNA, PFHpA, and PFDA (MCL)
Regulatory information
Concentration level
6 ppt
Chemical(s) and type of regulation
PFNA (MCL)
Regulatory information
Regulation and related information
Concentration level
8 ppt
Chemical(s) and type of regulation
PFOA (MCL)
Regulatory information
Regulation and related information
Concentration level
16 ppt
Chemical(s) and type of regulation
PFOS (MCL)
Regulatory information
Regulation and related information
Concentration level
51 ppt
Chemical(s) and type of regulation
PFHxS (MCL)
Regulatory information
Concentration level
0.0079 ppt
Chemical(s) and type of regulation
PFOA (Guidance)
Regulatory information
Health Advisory and related information
Concentration level
2.3 ppt
Chemical(s) and type of regulation
PFOS (Guidance)
Regulatory information
Health Advisory and related information
Concentration level
47 ppt
Chemical(s) and type of regulation
PFHxS (Guidance)
Regulatory information
Concentration level
1.97 ppt (stated by the Nevada Division of Environmental Protection as 0.00197 µg/L)
Chemical(s) and type of regulation
PFOA (Guidance)
Regulatory information
Concentration level
.00266 ppt (stated by the Nevada Division of Environmental Protection as 0.00000266 µg/L)
Chemical(s) and type of regulation
PFOA (Guidance)
Regulatory information
Concentration level
11 ppt
Chemical(s) and type of regulation
PFNA (MCL)
Regulatory information
Regulation and related information
Concentration level
12 ppt
Chemical(s) and type of regulation
PFOA (MCL)
Regulatory information
Regulation and related information
Concentration level
15 ppt
Chemical(s) and type of regulation
PFOS (MCL)
Regulatory information
Regulation and related information
Concentration level
18 ppt
Chemical(s) and type of regulation
PFHxS (MCL)
Regulatory information
Concentration level
13 ppt
Chemical(s) and type of regulation
PFNA and PFOS (MCL)
Regulatory information
Regulation and related information
Concentration level
14 ppt
Chemical(s) and type of regulation
PFOA (MCL)
Regulatory information
Concentration level
10 ppt
Chemical(s) and type of regulation
PFOA and PFAS (MCL)
Regulatory information
Regulation and related information
Concentration level
10 ppt
Chemical(s) and type of regulation
GenX or HFPO-DA (Guidance)
Regulatory information
Concentration level
4 ppt
Chemical(s) and type of regulation
PFOS and PFOA (Guidance)
Regulatory information
Concentration level
10 ppt
Chemical(s) and type of regulation
PFHxS, PFNA, and Gen X (Guidance)
Regulatory information
Concentration level
14 ppt
Chemical(s) and type of regulation
PFOA (MCL)
Regulatory information
Regulation and related information
Concentration level
18 ppt
Chemical(s) and type of regulation
PFOS (MCL)
Regulatory information
Concentration level
20 ppt
Chemical(s) and type of regulation
6 PFAS substances combined: PFOA, PFOS, PFHxS, PFNA, PFHpA, and PFDA (Notification)
Regulatory information
Concentration level
20 ppt (stated in the regulation as 0.000002 mg/L)
Chemical(s) and type of regulation
5 PFAS substances combined: PFOA, PFOS, PFHpA, PFHxS, and PFNA (MCL)
Regulatory information
Concentration level
9 ppt
Chemical(s) and type of regulation
PFNA (Notification)
Regulatory information
Concentration level
10 ppt
Chemical(s) and type of regulation
PFOA (Notification)
Regulatory information
Concentration level
15 ppt
Chemical(s) and type of regulation
PFOS (Notification)
Regulatory information
Concentration level
65 ppt
Chemical(s) and type of regulation
PFHxS (Notification)
Regulatory information
States that have adopted a standard equal to 70 ppt |
Concentration level
70 ppt
Chemical(s) and type of regulation
5 PFAS substances combined: PFOS, PFOA, PFNA, PFHxS, and PFHpA (Guidance)
Regulatory information
Concentration level
70 ppt (stated in the regulation as 70 ng/L)
Chemical(s) and type of regulation
3 PFAS substances combined: PFOS, PFOA, and PFNA (Guidance)
Regulatory information
Concentration level
70 ppt
Chemical(s) and type of regulation
PFOS, PFHxS and PFOA combined (Guidance)
Regulatory information
Concentration level
70 ppt
Chemical(s) and type of regulation
PFOS and PFOA combined (MCL)
Regulatory information
States that have adopted a standard higher than 70 ppt |
Concentration level
500 ppt (stated (stated by the California Water Boards as as 0.0005 mg/L)
Chemical(s) and type of regulation
PFBS (Notification)
Regulatory information
Concentration level
700 ppt (stated in the regulation as 700 ng/L)
Chemical(s) and type of regulation
PFHxS (Guidance)
Regulatory information
Translation Level and related information
Concentration level
400,000 ppt (stated in the regulation as 400,000 ng/L)
Chemical(s) and type of regulation
PFBS (Guidance)
Regulatory information
Concentration level
240 ppt
Chemical(s) and type of regulation
PFHxA (Notification)
Regulatory information
Action Level and related information
Concentration level
760 ppt
Chemical(s) and type of regulation
PFBS (Notification)
Regulatory information
Action Level and related information
Concentration level
1,800 ppt
Chemical(s) and type of regulation
PFBA (Notification)
Regulatory information
Concentration level
2,000 ppt (stated by the Illinois Environmental Pollution Control Agency as 2,000 ng/L)
Chemical(s) and type of regulation
PFBS (Guidance)
Regulatory information
Concentration level
140 ppt
Chemical(s) and type of regulation
PFHxS (Guidance)
Regulatory information
Concentration level
370 ppt
Chemical(s) and type of regulation
Gen X or HFPO-DA (MCL)
Regulatory information
Regulation and related information
Concentration level
420 ppt
Chemical(s) and type of regulation
PFBS (MCL)
Regulatory information
Regulation and related information
Concentration level
400,000 ppt
Chemical(s) and type of regulation
PFHxA (MCL)
Regulatory information
Concentration level
100 ppt
Chemical(s) and type of regulation
PFBS (Guidance)
Regulatory information
Health Advisory and related information
Concentration level
200 ppt
Chemical(s) and type of regulation
PFHxA (Guidance)
Regulatory information
Health Advisory and related information
Concentration level
7,000 ppt
Chemical(s) and type of regulation
PFBA (Guidance)
Regulatory information
Concentration level
10,000 ppt (stated by the Nevada Division of Environmental Protection as 10 µg/L)
Chemical(s) and type of regulation
PFBS (Guidance)
Regulatory information
Concentration level
2,000 ppt
Chemical(s) and type of regulation
PFBS (Guidance)
Regulatory information
Concentration level
345 ppt
Chemical(s) and type of regulation
PFBS (Notification)
Regulatory information
No state-specific PFAS drinking water regulations (as of the date of publication):
Alabama, Arizona, Arkansas, Florida, Georgia, Idaho, Indiana, Iowa, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Montana, Nebraska, North Dakota, Oklahoma, Oregon, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, and Wyoming.
How Do These Limits Impact Businesses?
MCLs apply to a PWS or CWS by setting the maximum concentration of a given contaminant that can be present in drinking water distributed to customers or the public. While PFAS drinking water regulations directly impact public water systems or municipalities, businesses and entities that currently or historically have used PFAS compounds should evaluate:
- Whether their discharges, either directly or following treatment by the POTW or other treatment facilities, are eventually released to sources of drinking water;
- Whether their discharges contain any of the PFAS compounds that are regulated within their jurisdiction; and
- Whether they are likely to be subject to permit conditions limiting the allowable concentration of PFAS compounds in their discharges, emissions, or other operations.
Acquiring this information will help businesses evaluate whether it may be appropriate to modify their operations to reduce and/or eliminate PFAS compounds from their waste stream(s), or in anticipation of future permit conditions or regulatory requirements.
Conclusion
The regulation of PFAS compounds in drinking water will continue to develop as additional research is conducted, and as regulators at both the federal and state levels continue to refine their understanding of the presence of PFAS compounds in drinking water and the efficacy of different MCLs.
For more information on PFAS chemicals, and the regulatory and liability considerations that they pose, please visit our PFAS webpage. If you have a question about how to manage PFAS risk in any jurisdiction, contact Erin Brooks, Jen Dempsey, Christian Bromley, Daron Ravenborg, John Kindschuh or any other member of our PFAS team at BCLP.
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