Wastewater can contain PFAS from the personal use and other products that enter the wastewater.  Fire-fighting foam also can contain PFAS. Military bases and airfields that have conducted fire-fighting training are common sources.


Based on current U.S. EPA approved methods, the health advisory levels for PFOA and PFOS are below the level of both detection (determining whether or not a substance is present) and quantitation (the ability to reliably determine how much of a substance is present). This means that it is possible for PFOA or PFOS to be present in drinking water at levels that exceed health advisories even if testing indicates no level of these chemicals.

Based on current U.S. EPA approved methods, the health advisory levels for GenX chemicals and PFBS are above both the detection and quantitation levels, and therefore can be reliably measured using specified analytical methods in appropriate laboratory settings. Please see the below table for more information.

In EPA’s fifth Unregulated Contaminant Monitoring Rule (UCMR 5), the agency established minimum reporting levels (MRLs) for the UCMR 5 contaminants, including 29 PFAS chemicals. EPA establishes MRLs to ensure consistency in the quality of the information reported to the agency. The MRL is the minimum quantitation level that, with 95 percent confidence, can be achieved by capable analysts at 75 percent or more of the laboratories using a specified analytical method (recognizing that individual laboratories may be able to measure at lower levels). The UCMR5 MRLs for these four PFAS and the health advisories are summarized in the table below:


Minimum Reporting Level (ppt)

Lifetime Health Advisory Level (ppt)



0.004 (Interim)



0.02 (Interim)

GenX Chemicals


10 (Final)



2,000 (Final)

PFAS do not break down or go away in the environment. If they are removed from drinking water on a filter, they will be either be disposed of in a landfill or incinerated. If incinerated, PFASs may not be destroyed, but can be released back into the air and enter the water cycle again. These compounds have been found in rainwater samples, and one or more PFAS is found in the blood of most Americans, at low levels. 

U.S. EPA and CDC research is ongoing to understand the human health effects from the compounds at these low levels. U.S. EPA issued the interim updated health advisories for PFOA and PFOS are based on human studies in populations exposed to these chemicals. Human studies have found associations between PFOA and/or PFOS exposure and effects on the immune system, the cardiovascular system, human development (e.g., decreased birth weight), and cancer. The final health advisories for GenX chemicals and PFBS are based on animal studies following oral exposure to these chemicals. GenX chemicals have been linked to health effects on the liver, the kidney, the immune system, and developmental effects, as well as cancer. PFBS has been linked to health effects on the thyroid, reproductive system, development, and kidney.

In the meantime, avoid using or purchasing products with PFAS so they do not enter the environment.

PFAS are a group of thousands of man-made chemicals that are fire, oil, grease, water and stain resistant, and are found in a wide array of consumer and industrial products, including non-stick cookware, stain repellant, dental floss, cleaning products, and cosmetics.

Some PFAS are now known to be bad for human health. While there are hundreds of banned PFAS, there are thousands more in existence, and more than 600 still used commercially in the United States. 

  • Read notices and updates from DC Water that provide updates on the status of PFAS in the District’s drinking water.
  • Avoid using or consuming products that contain any PFAS related chemicals. (PTFE or perfluoro- or polyfluor- anything).
  • Cook with stainless steel, cast-iron, glass, or ceramics. Don’t use nonstick cookware.
  • Look for coats, hats, and boots labeled water-resistant. They’re less likely to have PFAS than waterproof products.
  • 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.
  • Support efforts to protect drinking water sources from PFAS.
  • If you have questions or concerns about products you use in your home, contact the Consumer Product Safety Commission at or call (800) 638-2772.
  • Consider installing home treatment (e.g., filters) that are certified to lower the levels of PFAS in drinking water. See EPA’s website for more information at Please note the current NSF certification is to 70 ppt, which is higher than the EPA’s Health Advisory Level, so you need to research the filter to ensure it treats to your desired level.

Following U.S. EPA’s new guidance for addressing PFAS, DC Water will meet with our regulator, EPA Region III and discuss additional water testing to better understand the occurrence of these chemicals in our drinking water. DC Water was already on schedule to test for PFAS in 2023, but we are working with EPA Region III to review our sampling plan and adjust to best assess the occurrence of these chemicals.

U.S. EPA’s fifth Unregulated Contaminants Monitoring Rule requires water utilities to monitor for 29 PFAS chemicals between 2023 and 2025.  The Safe Drinking Water Act requires the U.S. EPA once every five years to issue list of unregulated contaminants to be monitored by water system. This is to provide EPA and other parties with scientifically valid data on the national occurrence of these contaminants in drinking water.  Water systems have a deadline of December 31, 2022, to update sampling locations to begin sampling in 2023.

DC Water and other utilities that use water from the Potomac River have been testing for PFAS for many years. The results were non-detect through 2020; however, the analytical methods were not as good as today’s methods (2,000 ppt in 2014 compared to 4 ppt or less today).  Washington Aqueduct treated water was tested by some Virginia utilities in 2021 and their results were non-detect at Method Reporting Limits of 3.9 ppt.  Washington Aqueduct treated water was also tested by DoD facilities in Virginia and the District of Columba in 2021 and detected PFOA and PFOS at levels of 3.6 ppt and 2.8 ppt with Method Reporting Limits of 1.7 ppt. 

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