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FACTS ABOUT PFAS

Poly- and Perfluoroalkyl Substances (PFAS) Overview and Current Activities

PFAS are a group of over 6,000 man-made chemicals that have been manufactured and used in home consumer products such as carpets, clothing, food packaging, and cookware since the 1940s. Two of these compounds—Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic acid (PFOS)—which are both widely produced and used forms of PFAS, have been the most extensively produced and studied, and there is evidence that exposure to elevated levels of PFAS can lead to adverse health outcomes in humans.

Water utilities are “passive receivers” of PFAS.  They do not produce or manufacture PFAS.  Instead, these chemicals may be present in source waters that are treated to produce drinking water.  Additionally, our region is collaborating to identify manufacturing and industrial facilities that may be contributors of PFAS to area source waters.

Regulations for PFAS

The Environmental Protection Agency (EPA) is responsible for setting regulatory limits under the federal Safe Drinking Water Act. 

Below is a timeline of EPA's steps toward regulating PFAS:

  • On April 10, 2024, EPA announced the final National Primary Drinking Water Regulation for six PFAS. Read Loudoun Water's Statement HERE.
  • On March 14, 2023, EPA announced the proposed National Primary Drinking Water Regulation for PFAS. Read Loudoun Water's Statement HERE.

Loudoun Water PFAS Analysis

In addition to testing, Loudoun Water has closely followed the US EPA’s drinking water regulatory process. On April 10, 2024, the EPA announced the final national primary drinking water regulation for six PFAS including proposed Maximum Contaminant Levels (MCLs) for perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), hexafluoropropylene oxide dimer acid (HFPO-DA or GenX chemicals), perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). The standard also establishes a hazard index (HI) for a mixture of two or more of the following: PFNA, PFHxS, HFPO-DA, and perfluorobutane sulfonic acid (PFBS). The EPA mandates that monitoring efforts begin by 2027.

What do Loudoun Water’s PFAS Results show?

Loudoun Water has tested for PFAS beginning in 2013, when PFAS chemicals were included in the Unregulated Contaminant Monitoring Rule (UCMR 3) rule was put into effect. Additionally, as a wholesale purchaser of drinking water from Fairfax Water, Loudoun Water is working closely in the region to understand PFAS implications as a regional initiative. 

Loudoun Water has begun developing our monitoring program in accordance with the regulatory requirements, and will share those results in future Water Quality Reports, starting in 2026.
According to the EPA, public water systems have five years (by 2029) to implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed these MCLs. Loudoun Water will ensure that our water meets these standards.

1 Hazard Index is a tool used by EPA that is made up of a sum of fractions. Each fraction compares the level of each PFAS measured in the water to the highest level determined not to have risk of health effects.

* On May 14, 2025, the U.S. Environmental Protection Agency (EPA) announced its intention to rescind the drinking water limits for four specific per- and polyfluoroalkyl substances (PFAS) and a related hazard index. Further communication is expected in the fall of 2025.  

Summary:

  • PFBS – all results are non-detect.
  • GenX – all results are non-detect.
  • PFOS and PFOA
    • Only a single sample was detected above the HA levels. All other samples collected at the same location and throughout the rest of the system were non-detect.
    • At this time, the lowest level that instruments can detect is 2 ppt, therefore results cannot be quantified down to the EPA’s Interim HA levels for PFOS and PFOA.
  • If results are above the 2022 HA level (see Health Advisories information below), what does that mean for customers? 
    • This is not an emergency or a regulatory violation.  If it had been, customers would have been notified within 24 hours. 
    • 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.
    • At this time, EPA is not recommending bottled water for communities based solely on concentrations of these chemicals in drinking water that exceed the health advisory levels.

Loudoun Water’s Next Steps

  • We are continuing to monitor the EPA legislation and we will move forward to meet the 2029/2031 proposed compliance schedule. 
  • We are following the guidance of EPA and VDH Office of Drinking Water
  • We have participated in EPA’s Unregulated Contaminant Monitoring Rule (UCMR5) which included PFAS analysis. Results can be found in our Water Quality Report.
  • We await further guidance and will take action if necessary to meet future state and federal regulations when they are established.
  • We will actively collaborate with our regional and national partners to further learn and adapt to how we can monitor and address PFAS to ensure public health and safe drinking water

Reducing Your Exposure to PFAS

  • Support efforts to protect drinking water sources and keep PFAS out of water supplies.
  • Cook with stainless steel, cast-iron, glass, or ceramics. Don’t use nonstick cookware.
  • Read ingredient lists and choose products without PTFE or perfluoro- or polyfluor-.
  • Look for coats, hats, and boots labeled water-resistant. They’re less likely to have PFAS than waterproof products.
  • Make popcorn on the stove or in an air popper instead of microwave bags.
  • Steer clear of ordering food in grease-resistant wrappers or containers.
  • Avoid carpets and upholstery treated to be stain or water-resistant; decline stain treatment.
  • Ask manufacturers if their products contain PFAS. These chemicals are often not listed.

Additional Information