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

To continue to build our understanding of PFAS occurrence, Loudoun Water commissioned voluntary testing across our drinking water systems starting in 2021 with an independent lab using current EPA-approved methods that can detect PFAS at much lower concentrations than previous methods. Loudoun Water also participated in the Virginia Department of Health (VDH) Occurrence Study that was completed in 2021. 

What do Loudoun Water’s PFAS Results show?

Loudoun Water participated in PFAS sampling events for our drinking water Central System throughout 2021-2022, both as an independent utility, and in collaboration with the Virginia Department of Health (VDH). Below is a summary of the range measured during these sampling events:

1 Lowest level that an instrument can detect is 2 ppt.

2 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.


  • 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 following the guidance of EPA and VDH Office of Drinking Water
  • We will also be collecting PFAS samples in 2023 for the EPA’s Unregulated Contaminant Monitoring Rule (UCMR5).
  • 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


Virginia Department of Health (VDH) Occurrence Study

Two bills passed in Virginia in 2020 (HB 586 and HB 1257) direct the VDH 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 several of those compounds.  In 2021, ODW collected and analyzed samples in source water and finished water at the 17 largest waterworks (including Loudoun Water) across the state. Results are available on the VDH website here.

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