Block 3

 

 

 

Block 4

PER- AND POLYFLUOROALKYL SUBSTANCES (PFAS)

PFAS are a class of thousands of different chemicals that have been manufactured and used in a variety of commercial products since the 1940s – from everyday household items to food packaging – due to its heat, moisture, and stain resistance and non-stick qualities. PFOA and PFOS have been the most extensively produced and studied of these chemicals, followed by PFHxS and PFNA. These chemicals do not break down in the environment or human body, and can accumulate over time. There is evidence that PFAS exposure can lead to adverse health effects.

ASDWA Focus on PFAS in Drinking Water

ASDWA facilitates engagement and develops resources to support state drinking water program PFAS regulations, policies, and actions for drinking water utilities across the nation. These efforts help protect public health by identifying and mitigating PFAS contamination at customer taps and in their drinking water sources.

ASDWA promotes using a holistic lifecycle approach that considers PFAS impacts across all environmental media and from manufacturing through disposal of products containing PFAS. Protecting drinking water sources is much more effective and less expensive than having states, drinking water utilities, and their customers pay to remove PFAS once drinking water has become contaminated.

PFAS Background: The understanding of potential drinking water impacts from PFAS has significantly increased over the past decade. This class of chemicals started to get publicity in 2001 & 2002 due to water contamination from the Washington Works Plant located outside of Parkersburg, West Virginia, on the West Virginia/Ohio border. The class-action lawsuit against DuPont due to water contamination at Little Hocking Water District and Lubeck Public Service District generated additional publicity. In 2006, DuPont and other manufacturers such as 3M, agreed to principally phase out the production of PFOA and PFOS.

The Number of PFAS Being Manufactured Continues to Grow: There are thousands of PFAS compounds being used in commerce. Since the phase-out of PFOA and PFOS, companies have shifted to “short-chain” PFAS. Except for the 29 PFAS on UCMR5, current analytical methods are unable to detect these other short-chain compounds. The increasing number of PFAS of concern is creating a host of data collection and analysis issues, as regulators and researchers are struggling to get enough robust health effects, analytical methods, and treatment data to enable decision-making.

EPA’s Final National Primary Drinking Water Regulation (NPDWR) for Six PFAS

On April 26, 2024, EPA released the Final NPDWR for PFOA and PFOS, and four additional PFAS. EPA set a Maximum Contaminant Level (MCL) of 4 parts per trillion (ppt) for PFOA and  PFOS, and 10 ppt for PFHxS, PFNA, and HFPO-DA (GenX). In addition to these five MCLs, EPA included a Hazard Index for mixtures of two or more of four PFAS including PFHxS, PFNA, GenX, and PFBS. The Hazard Index 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. Additionally, EPA has finalized Maximum Contaminant Level Goals (MCLGs) for each of the six PFAS. The MCLs and MCLGs are as follows.

  Compound Name Final MCLG Final MCL
PFOA Perfluorooctanoic acid 0 ppt 4.0 ppt
PFOS Perfluorooctanesulfonic acid 0 ppt 4.0 ppt
GenX Hexafluoropropylene oxide dimer acid 10 ppt 10 ppt
PFHxS Perfluorohexanesulfonic acid 10 ppt 10 ppt
PFNA Perfluorononanoic acid 10 ppt 10 ppt
Mixture Two or more of PFHxS, PFNA, GenX, and PFBS HI* = 1 HI* = 1

*Hazard Index (HI) is unitless

For the Hazard Index, the rule uses a ratio for two or more of the four PFAS to calculate a compliance value based on detected levels of PFAS. If the combination of ratios is at or above 1 (unitless), then water systems are expected to reduce the levels of these PFAS.

EPA PFAS Drinking Water Actions Timeline

HAs Versus Regulatory Standards

Use of HAs as guidance, versus a SDWA regulation with an established MCL created challenges for state drinking water programs and public water systems. Because they are not legally enforceableand and do not consider feasibility, costs, or benefits of reducing contaminant levels like a federal NPDWR. The HAs also do not clarify necessary actions for water systems to address the compounds, and how to communicate their actions and the associated health risks to the public. 

In the case of PFOA and PFOS: The interim health advisories were intended to be in place during the time interval between initial understanding of health effects and publication of the final health advisory or maximum contaminant level goal (MCLG) and NPDWR.

EPA’s Health Advisories (HAs) for PFAS: EPA’s PFAS HAs for drinking water began with the first and highest levels for PFOA and PFOS in 2009. These levels were lowered in 2016 and again in 2022 based on new data and health studies. These HAs informed the development of the PFAS NPDWR. 

EPA PFAS Health Advisories

  Compound Name 2009 EPA HAs 2016 Revised HAs 2022 EPA HAs
PFOA Perfluorooctanoic acid 400 ppt 70 ppt (individual and combined sum with PFOS) .004 ppt*
PFOS Perfluorooctanesulfonic acid 200 ppt 70 ppt (individual and combined sum with PFOA) .02 ppt*
GenX Hexafluoropropylene oxide dimer acid NA NA 10 ppt
PFBS Perfluorobutane sulfonic acid NA NA 2000 ppt

*EPA interim HA levels.

 

ASDWA PFAS – Source Water Protection Guide and Toolkit

ASDWA developed this guide and toolkit with support from a Project Advisory Council (PAC) with representatives from nine states (Colorado, Kansas, Minnesota, New Hampshire, North Carolina, Pennsylvania, Vermont, Virginia, and Wisconsin), and the Cadmus Group. The purpose of the guide is to demonstrate and share effective strategies for addressing PFAS contamination risk in source waters that will help inform policy decisions, assist state drinking water programs in protecting public health, and encourage collaboration and communication among states and water utilities.


The tool includes three main components and a factsheet:

The ASDWA PFAS SWP – Decision Support Tool is downloadable in Excel and provides examples of state actions to address PFAS contamination. It includes an update form for states and other organizations to submit updates or new entries for the Tool.

The factsheet for Communicating with Industry on PFAS Contamination includes best practices and questions with fillable fields to support state planning efforts.

The Technical Appendix includes an overview of PFAS, chemicals of concern, PFAS in the U.S., and state PFAS profiles.

The Mapping Guide aids identifying and mapping source waters that are vulnerable to PFAS contamination.

Download The Guide and Toolkit

Learn More About the Toolkit – in this webinar, ASDWA showcases the newly developed PFAS Source Water Protection Guide and Toolkit, sharing effective strategies for addressing PFAS contamination risk in source waters.

State PFAS Standards and Guidelines

Before the final NPDWR was published, some states developed their own PFAS standards and guidelines. These states acted to protect the public health from the impacts of  PFAS contaminated drinking water in the absence of a federal rule. The table below shows the states that proposed or established PFAS standards or guidelines before the Final NPDWR was published. These numbers demonstrate the variation in health risk goals and risk reductions among states in the absence of federal standards and are creating public confusion about what levels of PFAS are safe in drinking water.

State Actions to Address PFAS in Drinking Water

State Drinking Water Action Compound Level (ppt)
California

Response Levels

Notification Levels

PFOA

PFOS

PFBS

PFOA

PFOS

PFBS

10

40

5000

5.1

6.5

500

Connecticut Action Level Sum of PFOA, PFOS, PFNA, PFHxS, PFHpA 70
Illinois Health Advisory Levels 7/27/21

PFOA

PFOS

PFNA

PFHxS

PFBS

PFHxA

2

14

21

140

2100

560,000

Massachusetts Adopted Regulation 9/16/20 Sum of PFOA, PFOS, PFNA, PFHxS, PFHpA, PFDA 20
Michigan Adopted Regulation 8/3/20

PFOA

PFOS

PFNA

PFHxS

PFBS

PFHxA

GenX

8

16

6

51

420

400,000

370

Minnesota

Health Based Guidance for Water

Surrogate of PFOS HBV

PFOA

PFOS

PFHxS

35

15

47

New Hampshire Adopted Regulation 10/1/19

PFOA

PFOS

PFHxS

PFNA

12

15

18

11

New Jersey

Adopted Regulation

Adopted Regulations 6/1/20

PFNA

PFOA

PFOS

13

14

13

New York Adopted Regulation 7/30/20

PFOA

PFOS

10

10

North Carolina Health Advisory GenX 140
Vermont Adopted Regulation 3/17/20 Sum of PFOA, PFOS, PFNA, PFHxS, PFHpA 20
Washington State Action Levels 1/1/22

PFOA

PFOS

PFNA

PFHxS

PFBS

10

15

9

65

345

Wisconsin Adopted Regulation 8/1/22 Sum of PFOA and PFOS 70

Click to expand the section below to see more examples of state efforts:

State PFAS Sampling Maps – Action Plans – Resources

Drinking Water Treatment Resources

For more information on how states are addressing PFAS, contact Deirdre White at dwhite@asdwa.org

ASDWA PFAS Fact Sheet

Download a PDF-version of this webpage.


ASDWA’s PFAS News Feed

ASDWA publishes content covering various areas of the drinking water program.

Learn More

PFAS Water System Superfund Liability Relief Bill Reintroduced in House

February 18th, 2025 Deirdre White On February 12, House Representatives Marie Gluesenkamp Perez (D-WA) and Celeste Maloy (R-UT) reintroduced H.R. 1267, the “Water Systems PFAS Liability Protection Act.” This bipartisan bill is aimed at protecting water and wastewater systems from Superfund liability under the Comprehensive Environmental Response, Compensation & Liability Act (CERCLA), as passive receivers of PFAS contamination. EPA designated PFOA…

State Attorneys General File Amicus Brief Defending EPA’s PFAS Drinking Water Rule

January 28th, 2025 Deirdre White On January 17, seventeen states and the District of Columbia filed an Amicus Brief in the U.S. Court of Appeals for the D.C. Circuit defending EPA’s National Primary Drinking Water Regulation (NPDWR (rule)) for six PFAS. The Amicus Brief states that the PFAS rule supports the states’, “interests in protecting their residents from the harms…

OMB Withdraws EPA’s PFAS Effluent Limitation Guidelines and Standards Proposed Rule

January 24th, 2025 Deirdre White On January 21, 2025, the Office of Management and Budget (OMB) withdrew EPA’s Proposed Rule on “Clean Water Act Effluent Limitations Guidelines (ELG) and Standards for PFAS Manufacturers Under the Organic Chemicals, Plastics and Synthetic Fibers (OCSPF) Point Source Category.” The withdrawal was based on President Trump’s Executive Order for a Regulatory Freeze Pending Review…