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PFAS & Drinking Water FAQ

PDF icon Service Authority Addresses Proposed PFAS Rules

Click on a topic below to view the answers.

What are perfluoroalkyl and polyfluoroalkyl substances (PFAS)?

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a class of more than 6,000 manmade chemicals used in the manufacture of a wide variety of industrial and household products designed to resist heat, water, oil and stains. A wide variety of products are made with PFAS, including non-stick cookware, food packaging, personal care products and water-resistant apparel.

Four PFAS of note include perfluorooctanoic Acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (PFBS) and hexafluoropropylene oxide dimer acid (HPFO-DA or GenX). In June 2022, the Environmental Protection Agency (EPA) released new lifetime health advisories for the four compounds.

Although their use has been phased out in the United States, the fact that these chemicals are very stable means that they tend to hang around in the environment for a long time. There is national concern about these chemicals entering our surface and groundwater drinking water sources.

Is PFAS regulated in drinking water?

On March 14, 2023, EPA announced the proposed National Primary Drinking Water Regulation (NPDWR) for six PFAS including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX Chemicals), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS). The proposed PFAS NPDWR does not require any actions until it is finalized. EPA anticipates finalizing the regulation by the end of 2023. EPA expects that if fully implemented, the rule will prevent thousands of deaths and reduce tens of thousands of serious PFAS-attributable illnesses.

EPA is requesting public comment on the proposed regulation. The public comment period will open following the proposed rule publishing in the Federal Register. Public comments can be provided at that time at www.regulations.gov under Docket ID: EPA-HQ-OW-2022-0114. Information on submitting comments to EPA dockets can be found here.

EPA will be holding two informational webinars about the proposed PFAS NDPWR on March 16, 2023, and March 29, 2023. The webinars will be similar, with each intended for specific audiences. Registration is required to attend. The webinar recordings and presentation materials will be made available following the webinars at this website. For questions related to the public webinars, contact PFASNPDWR@epa.gov

EPA will also be holding a public hearing on May 4, 2023, where members of the public can register to attend and provide verbal comments to EPA on the rule proposal. Registration is required to attend and the last day to register to speak at the hearing is April 28, 2023. For questions related to the public hearing, contact PFASNPDWR@epa.gov


EPA is proposing a National Primary Drinking Water Regulation (NPDWR) to establish legally enforceable levels, called Maximum Contaminant Levels (MCLs), for six PFAS in drinking water. PFOA and PFOS as individual contaminants, and PFHxS, PFNA, PFBS, and HFPO-DA (commonly referred to as GenX Chemicals) as a PFAS mixture. EPA is also proposing health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these six PFAS. 

The Hazard Index is a long-established tool that EPA regularly uses to evaluate health risks of simultaneous exposure to mixtures of related chemicals. To prevent health risks from mixtures of certain PFAS in drinking water, EPA is proposing that water systems use this Hazard Index approach to regulate PFHxS, GenX Chemicals, PFNA, and PFBS. To determine the Hazard Index for these four PFAS, water systems would monitor and compare the amount of each PFAS in drinking water to its associated Health- Based Water Concentration (HBWC), which is the level at which no health effects are expected for that PFAS. Water systems would add the comparison values for each PFAS contained within the mixture. If the value is greater than 1.0, it would be an exceedance of the proposed Hazard Index MCL for these four PFAS.

The proposed rule would also require public water systems to:

  • Monitor for these PFAS
  • Notify the public of the levels of these PFAS
  • Reduce the levels of these PFAS in drinking water if they exceed the proposed standards.

Has PWCSA tested its drinking water for PFAS?

In May 2021, the Prince William County Service Authority voluntarily participated in a Virginia Department of Health (VDH) study to analyze for PFAS in water samples collected from the distribution systems of the 17 largest water utilities in the state. The Service Authority collected samples from its East and West systems and sent them to an independent laboratory selected by VDH for testing. The test results are shown in the table below.

What actions are the EPA and the Virginia Department of Health (VDH) taking regarding PFAS?


On March 14, 2023, the EPA announced its proposed national drinking water standards for 6 types of Poly-and Perfluoroalkyl Substances (PFAS) including proposed Maximum Contaminant Levels (MCLs) for Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic acid (PFOS). The proposed standard also includes establishing a hazard index for a combination of four other PFAS compounds. For more information about the proposed standards, please visit https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas

In June 2022, EPA released interim health advisory levels of 0.004 ppt for PFOA and 0.02 ppt for PFOS. Additionally, final health advisories were released of 2,000 ppt for PFBS and 10 ppt for GenX chemicals.

In February 2021, the EPA issued a final determination to regulate PFOA and PFOS in drinking water. The agency also proposed to require water utilities monitor for 29 PFAS compounds in drinking water. In April 2021, the agency announced the establishment of the EPA Council on PFAS to develop a national strategy to protect public health and make recommendations regarding PFAS.

In December 2021, EPA published the fifth Unregulated Contaminant Monitoring Rule (UCMR 5). UCMR 5 requires sample collection for 30 chemical contaminants between 2023 and 2025, using analytical methods developed by EPA and consensus organizations. Twenty-nine PFAS chemicals will be included in this study.


In 2020, the Virginia General Assembly passed two bills (HB 586 and HB 1257) that directed the VDH’s Office of Drinking Water (ODW) to study the occurrence, health effects and treatability of PFAS compounds in public drinking water and to adopt maximum contaminant levels (MCLs) for some PFAS compounds.

What is PWCSA doing about PFAS?

The Service Authority purchases treated drinking water from Fairfax Water and the City of Manassas to meet the needs of Service Authority customers in Prince William County. The Service Authority remains fully confident in their ability to provide safe and reliable drinking water that meets regulatory treatment and distribution requirements. Click here for more information from Fairfax Water. https://www.fairfaxwater.org/news/epa-announces-proposed-pfas-regulations

The Service Authority is studying EPA’s proposed rule along with our regional and national water utility colleagues. As we gain a clearer understanding of the implications of the proposed rule on Service Authority operations, information will be shared with our customers. The Service Authority will take all necessary actions to meet federal and state drinking water regulations for PFAS.

How does PFAS get into drinking water sources?

PFAS typically enters drinking water sources (lakes, rivers, wells, etc.) through storm water runoff and wastewater originating from facilities where PFAS chemicals were produced or used.

PFAS are slow to break down and using products with PFAS puts these chemicals into the environment, where, over time, they may end up in drinking water supplies. PFAS can also enter the environment as consumers wash and throw away products containing these chemicals and through bodily waste.

How can I limit my exposure to PFAS?

  • Read labels and try to avoid using products with PFAS, like some non-stick cookware, paints, degreasers and fire-fighting foams, as well as products like waterproof and water-resistant clothing, certain cosmetics, stain-resistant upholstery and carpet, and food packaged in grease-proof wrappers or containers.
  • Avoid products containing ingredients listed as PTFE or perfluoro-, or polyfluor-.
  • Support efforts to protect drinking water sources from PFAS.

If you are concerned about potential health effects from exposure to these PFAS above the health advisory level, EPA encourages you to contact your doctor or health care professional.

Where can I learn more about PFAS?