SUMMARY
In the absence of an enforceable federal drinking water standard for per- and polyfluoroalkyl substances (“PFAS”) – for the time being anyway - many states have regulated 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.
FEDERAL ACTIONS
EPA took two significant actions in 2023 to move towards establishing drinking water limits for certain PFAS substances. Additionally, there is one proposed action that the Federal Government intends to enact in 2024.
MAXIMUM CONTAMINANT LEVELS
According to the PFAS Strategic Roadmap, the United States Environmental Protection Agency (“EPA”) originally planned to issue proposed MCLs for PFOA and PFOS in drinking water by the end of 2022. At this time, the regulation states that the final rule will be issued in January of 2024, but it is unclear whether this date will be pushed back. Not surprisingly, EPA received extensive public comments in response to the proposal, so it may be some time before it finalizes the rule.
On March 14, 2023, EPA proposed a National Primary Drinking Water Regulation for six PFAS compounds, going beyond the two compounds that were originally contemplated by the Roadmap. Specifically, EPA proposed in the Federal Register the following MCLs and Maximum Contaminant Level Goals (“MCLGs”) for the six compounds:
Proposed MCLG
Zero
Proposed MCL (enforceable levels)
4.0 parts per trillion (also expressed as ng/L)
4.0 ppt
Proposed MCLG
Zero
Proposed MCL (enforceable levels)
4.0 parts per trillion (also expressed as ng/L)
4.0 ppt
Proposed MCLG
1.0 (unitless)
Hazard Index
Proposed MCL (enforceable levels)
1.0 (unitless)
Hazard Index
Proposed MCLG
1.0 (unitless)
Hazard Index
Proposed MCL (enforceable levels)
1.0 (unitless)
Hazard Index
Proposed MCLG
1.0 (unitless)
Hazard Index
Proposed MCL (enforceable levels)
1.0 (unitless)
Hazard Index
Proposed MCLG
1.0 (unitless)
Hazard Index
Proposed MCL (enforceable levels)
1.0 (unitless)
Hazard Index
As discussed in more detail in our BCLP alert regarding this proposal, there are three aspects that are particularly noteworthy:
- EPA decided to include four additional PFAS compounds beyond PFOA and PFOS, demonstrating that the agency’s focus extends beyond those two compounds.
- EPA’s 4 ppt MCLs for PFOA and PFOS are incredibly low, but the agency set the MCLGs for both compounds at zero and explained that EPA is allowing 4 ppt as the MCL because that is the lowest detection level that is generally achievable at commercial laboratories. EPA has indicated that it will continue to reduce the MCLs for those two compounds as testing methodologies improve.
- Rather than establish simple numeric concentration limits for the four new PFAS compounds, EPA implemented a Hazard Index (“HI”) approach for all four compounds combined. EPA used the HI based on its conclusion that PFAS compounds are often commingled, and that can result in an additive health impact. While not unprecedented, this HI approach will create challenges as water systems try to implement testing and controls to try to meet these standards.
While EPA has yet to issue any final MCLs, their proposal clearly indicates that EPA intends to aggressively regulate these six compounds in drinking water.
UCMR 5 – DRINKING WATER SYSTEM DATA
The latest iteration of the UCMR rule requires public drinking water systems to collect samples for 29 PFAS substances and lithium, during a single 12-month period at any time from January 2023 through December 2025, and report that data to EPA. In October 2023, EPA released the second set of UCMR 5 data, representing approximately 15% of the total data that it expects to collect. EPA highlighted the following findings in its data summary:
- “PFOA and PFOS are two of the most widely studied PFAS, and each has an EPA Health Advisory (HA) level. One or each of these two PFAS was measured at or above the EPA’s UCMR minimum reporting level (MRL), and therefore above the agency’s HA levels, in the initial subset of sampling events for 13.6% of PWSs with results to date
- Individually, PFOA and PFOS were measured above the EPA HA levels for 9.5% and 10.7% of PWSs, respectively.
- The other two PFAS with EPA HA levels are HFPO-DA (“GenX chemicals”) and PFBS. HFPO-DA was measured above its HA level by 0.03% of PWSs (1 of 3,073). PFBS was not found above its HA level.
- HA levels have not been established for the other 25 PFAS that are part of UCMR 5.
- Fourteen of these 25 PFAS were measured at or above their respective UCMR MRL by at least one PWS.
- For the other 11 PFAS, no PWSs have reported results at or above their respective UCMR MRLs.”
While more data will be released as reporting continues, the findings thus far suggest that some public water systems will face compliance challenges as both EPA and states implement and enforce drinking water standards.
STATE REGULATIONS
Until the federal government finalizes its proposed MCLs for six PFAS compounds, 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 2 ppt (Illinois; PFOA only) to 400,000 ppt (Michigan; PFHxA 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 discrepancies between the regulatory levels for PFOA and/or PFOS.
The map and chart are current as of January 8, 2023, but this is a very active regulatory space, and additional state action is anticipated soon. For example, Delaware, Maine, and Virginia have enacted legislation to establish MCLs for PFAS compounds for drinking water, so implementing regulations in those jurisdictions may be forthcoming. Additionally, several states, including Indiana, Kentucky, Minnesota, North Carolina I, North Carolina II, South Carolina, and Vermont, have proposed, but not yet promulgated, various types of drinking water regulations for PFAS. Notably, proposed bills have been introduced in Maine and New York mandating the testing of drinking water in private wells (including numerous PFAS substances) during property transactions.
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
5.1 ppt (stated by the California Water Boards as 0.0000051 mg/L)
Chemical(s) and type of regulation
PFOA (Notification)
Regulatory information
Regulation and related information
Concentration level
6.5 ppt (stated by the California Water Boards as 0.0000065 mg/L)
Chemical(s) and type of regulation
PFOS (Notification)
Regulatory information
Regulation and related information
Concentration level
2 ppt
Chemical(s) and type of regulation
6:2 chloropolyfluoroether sulfonic acid (Notification)
9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid
Regulatory information
Action Level and related information
Concentration level
5 ppt
Chemical(s) and type of regulation
8:2 chloropolyfluoroether sulfonic acid (Notification)
11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid
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
Action Level and related information
Concentration level
2 ppt (stated by the Illinois Environmental Pollution Control Agency as 2 ng/L)
Chemical(s) and type of regulation
PFOA (Guidance)
Regulatory information
Regulation and related information
Concentration level
14 ppt (stated by the Illinois Environmental Pollution Control Agency as 14 ng/L)
Chemical(s) and type of regulation
PFOS (Guidance)
Regulatory information
Regulation and related information
Concentration level
21 ppt (stated by the Illinois Environmental Pollution Control Agency as 21 ng/L)
Chemical(s) and type of regulation
PFNA (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 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
Regulation and related 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
Regulation and related information
Concentration level
15 ppt
Chemical(s) and type of regulation
PFOS (Guidance)
Regulatory information
Health Advisory and related information
Concentration level
35 ppt
Chemical(s) and type of regulation
PFOA (Guidance)
Regulatory information
Health Advisory and related information
Concentration level
47 ppt
Chemical(s) and type of regulation
PFHxS (Guidance)
Regulatory information
Health Advisory and related information
Concentration level
6.67 ppt (stated by the Nevada Division of Environmental Protection as .0667 µg/L)
Chemical(s) and type of regulation
PFSA (Guidance)
Regulatory information
Basic Comparison Levels
Related information
Concentration level
10 ppt (stated by the Nevada Division of Environmental Protection as .1 µg/L)
Chemical(s) and type of regulation
PFOA (Guidance)
Regulatory information
Basic Comparison Levels
Related 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
Regulation and related 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
Regulation and related 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
Health Advisory and related information
Concentration level
21 ppt
Chemical(s) and type of regulation
PFNA (Guidance)
Regulatory information
Statewide PFAS Action Plan and related information
Concentration level
21 ppt
Chemical(s) and type of regulation
Gen X or HFPO-DA (Guidance)
Regulatory information
Statewide PFAS Action Plan and related information
Concentration level
30 ppt
Chemical(s) and type of regulation
4 PFAS substances combined: PFOS, PFOA PFHxS, and PFNA (Guidance)
Regulatory information
Health Advisory and related 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
Regulation and related 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
Interim Drinking Water Standard and related 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
Regulation and related information
Concentration level
9 ppt
Chemical(s) and type of regulation
PFNA (Notification)
Regulatory information
Code and related information
Concentration level
10 ppt
Chemical(s) and type of regulation
PFOA (Notification)
Regulatory information
Code and related information
Concentration level
15 ppt
Chemical(s) and type of regulation
PFOS (Notification)
Regulatory information
Code and related information
Concentration level
65 ppt
Chemical(s) and type of regulation
PFHxS (Notification)
Regulatory information
Code and related information
Concentration level
70 ppt
Chemical(s) and type of regulation
5 PFAS substances combined: PFOS, PFOA, PFNA, PFHxS, and PFHpA (Guidance)
Regulatory information
Action Level and related 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
Translation Level and related information
Concentration level
70 ppt
Chemical(s) and type of regulation
Adopted the EPA Standard: PFOS and PFOA combined (Notification)
Regulatory information
Notification Policy
Concentration level
70 ppt
Chemical(s) and type of regulation
Adopted the EPA Standard: PFOS and PFOA combined (Notification)
Regulatory information
Toxic Pollutant Standard
Concentration level
70 ppt
Chemical(s) and type of regulation
Adopted the EPA Standard: PFOS and PFOA combined (Guidance)
Regulatory information
Statewide PFAS Action Level and related information
Concentration level
70 ppt
Chemical(s) and type of regulation
PFOS and PFOA combined (MCL)
Regulatory information
Regulation and related information
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
Regulation and related 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
Translation Level and related 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
Action Level and related information
Concentration level
140 ppt (stated by the Illinois Environmental Pollution Control Agency as 140 ng/L)
Chemical(s) and type of regulation
PFHxS (Guidance)
Regulatory information
Regulation and related information
Concentration level
2,100 ppt (stated by the Illinois Environmental Pollution Control Agency as 2,100 ng/L)
Chemical(s) and type of regulation
PFBS (Guidance)
Regulatory information
Regulation and related information
Concentration level
3,500 ppt (stated by the Illinois Environmental Pollution Control Agency as 3,500 ng/L)
Chemical(s) and type of regulation
PFHxA (Guidance)
Regulatory information
Regulation and related information
Concentration level
140 ppt
Chemical(s) and type of regulation
PFHxS (Guidance)
Regulatory information
Health Advisory
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
Regulation and related 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
Health Advisory and related 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
Basic Comparison Levels
Related information
Concentration level
140 ppt
Chemical(s) and type of regulation
PFHxS (Guidance)
Regulatory information
Statewide PFAS Action Plan and related information
Concentration level
140,000 ppt
Chemical(s) and type of regulation
PFBS (Guidance)
Regulatory information
Statewide PFAS Action Plan and related information
Concentration level
345 ppt
Chemical(s) and type of regulation
PFBS (Notification)
Regulatory information
Code and related information
Concentration level
7.7 ppt, etc. (stated by the Hawaii Department of Health as 0.0077 µg/L)
- Hawaii has 19 additional regulations, including the following: PFDA (7.7 ppt); PFOA, HFPO-DA, and PFNA (12 ppt); PFUnDA (19 ppt); PFDoDA and PFTrDA (26 ppt); PFHpS and PFDS (38 ppt); PFOSA (46 ppt); PFHpA and PFHxS (77 ppt); PFTeDA (260 ppt); ADONA (1,200 ppt); PFPeA and 6:2 FTS (1,500 ppt); PFBS (1,700 ppt); PFHxA (1,900 ppt); and PFBA (15,000 ppt).
Chemical(s) and type of regulation
PFOS and 19 other PFAS substances (Guidance)
Regulatory information
Environmental Action Levels (Table D-3a)
*as of date of publication
- Alabama
- Arizona
- Arkansas
- Florida
- Georgia
- Idaho
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Mississippi
- Missouri
- Montana
- Nebraska
- North Dakota
- Oklahoma
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Virginia
- West Virginia
- Wyoming
Notification
A corporate representative may have to inform an appropriate state official that a drinking water concentration in a water source owned or operated by the corporation (public well, supply tank, etc.) is above the limit. A water supply system also may have to inform its customers if there are any samples that exceed the PFAS values.
Guidance
The state establishes recommended concentration limits for one or more PFAS substances, but no notification or other action is required if concentrations exceed the recommended limits.
MCL
MCLs establish the maximum amount of a PFAS compound that can be present in drinking water. Treatment facilities that supply drinking water must ensure that these limits are met by treating and filtering the drinking water, and also by limiting the discharge of PFAS compounds through permits.
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 limits for discharges to 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 effluent, should evaluate:
- 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 substances from their waste stream to achieve compliance with an existing standard, or in anticipation of likely future permit conditions.
CONCLUSION
The regulation of PFAS substances in drinking water will continue to develop over the next year 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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