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PFAS And Drinking Water

The EPA has issued an Interim Health Advisory for PFOA and PFOS to provide information to states and public water systems while they continue to develop regulations.


PFAS Found in everyday sources.

On June 15, 2022, the U.S. Environmental Protection Agency (U.S. EPA) released new drinking water health advisories for four related chemicals, known collectively as PFAS. 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. EPA reported Interim Drinking Water Health Advisories for two of these compounds—Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic acid (PFOS)— which have been the most extensively produced and studied. EPA also issued final Drinking Water Health Advisories for GenX Chemicals (hexafluoropropylene oxide) and Perflurobutane sulfuric acid and its related compound potassium perflurobutane sulfonate (PFBS).

PFAS are used in many applications because of their unique physical properties such as resistance to high and low temperatures, resistance to degradation, and nonstick characteristics. PFAS have been detected worldwide in the air, soil, and water. Due to their widespread use and persistence in the environment, most people in the United States have been exposed to PFAS. U.S. EPA has determined there is evidence that continued exposure above specific levels to certain PFAS may cause adverse health effects.

Regulatory Path

The science around these chemicals is evolving. Scientists are hard at work understanding the chemicals, their risk to human health, and how to mitigate that risk.

The U.S. EPA regulates drinking water and issues health advisories for contaminants. A health advisory provides information on a contaminant that can cause negative human health effects and is known or anticipated to occur in drinking water. U.S. EPA's health advisories are non-enforceable and non-regulatory. They usually provide technical information to drinking water system operators, as well as federal, state, Tribal, and local officials, on the health effects, analytical methods, and treatment technologies associated with drinking water contaminants. This health effects information includes the concentrations of such drinking water contaminants (the health advisory “levels” or “values”) at which adverse health effects are not anticipated to occur over specific exposure durations, such as one-day, 10-days or a lifetime.

The concentration levels within these new Health Advisories are below current testing method limits—0.004 parts per trillion (ppt) for PFOA and 0.02 ppt for PFOS. We are working with U.S. EPA to better understand the health risks when the sampling results are not detectable, but the testing method reporting limit is above the Health Advisory Level.

DC Water Path Forward

Locally, water utilities and military establishments have tested for PFAS.  Earlier laboratory analytical methods had minimum reporting limits of 4 ppt or higher, resulting in no detects for the Potomac River supplied water treatment plants. New EPA approved methods have minimum report levels of 2 ppt that are detecting PFAS more frequently.  The table below shows the data from local utilities and military establishments that used the new EPA approved methods. 

The Washington Aqueduct began PFAS monitoring in October 2022 from both their treatment plants. We will continue monitoring quarterly, and as we receive the results they will be posted here. 


Military Facilities

Virginia Utility1



Max Results

Method Reporting Limit

Max Results

Method Reporting Limit

EPA’s 2022 HA Level


3.6 ppt

1.7 ppt


2 ppt

0.02 ppt


2.8 ppt

1.7 ppt


2 ppt

0.004 ppt


2.4 ppt

1.7 ppt


2 ppt

2,000 ppt



1.7 ppt


2 ppt

10 ppt

1Fairfax Water is monitoring and updating their website at  Data in the table are from the sampling event in September 2022 that included the water delivered from the Washington Aqueduct. 

*ppt = parts per trillion

DC Water works with industry experts, scientists, regulators, and industry peers to understand health risks, how to mitigate them, and how to communicate them to everyone. These groups are knowledgeable in detection and treatment technologies for many contaminants; however, studies of this class of chemicals are relatively new. We look to EPA for further guidance as the science progresses.

  • DC Water is following the guidance of EPA Region 3, our regulating authority.
  • We are also closely monitoring federal regulatory updates for PFAS.
  • We will take necessary actions to meet any federal regulations when they are established.
  • DC Water continues to stress the importance of source water protection and its role in keeping drinking water supplies safe. Protecting drinking water sources and keeping PFAS away from water supplies is a priority.
  • Water utilities are “passive receivers” of PFAS. They do not produce or manufacture PFAS. Instead, these chemicals are present in source waters that are treated to produce drinking water.

Customer Action

Customer action is not required.  Results greater than the Health Advisory Levels do not mean that there is an emergency or violation. DC Water will advise if the circumstances change. 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. If you are concerned about potential health effects, from exposure to PFASs above Health Advisory Levels, EPA encourages you to contact your doctor or health care professional.

Steps to reduce 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.
  • 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.

For more information, please call DC Water’s Office of Drinking Water Quality and Technology at 202-612-3440 during business hours, email or refer to the resources below.