Understanding PFAS
Per- and Polyfluoroalkyl Substances
WSSC Water Prepared to Meet New Drinking Water Regulation on Forever Chemicals
WSSC Water’s priority is public health, providing Prince George’s and Montgomery counties with excellent quality drinking water. On April 10, 2024, the Environmental Protection Agency (EPA) published its final rule for a group of PFAS chemicals. These drinking water standards do not take effect until 2029, but our drinking water already meets them.
About the Standards and our Data
For two of the most common PFAS compounds, perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), the EPA today set a Maximum Contaminant Level (MCL) of 4.0 parts per trillion (ppt). For perspective, four parts per trillion is equivalent to one drop of water in five Olympic-sized swimming pools. The EPA also set a MCL of 10 ppt for PFHxS, PFNA and HFPO-DA (commonly called GenX). Additionally, EPA finalized a Hazard Index that creates an enforceable drinking water standard for any mixture of two or more of the following four PFAS compounds: PFNA, PFHxS, PFBS and HFPO-DA.
We want our 1.9 million customers to know that they can trust their taps - our drinking water meets the final standards. As an organization dedicated to protecting public health, we are committed to doing everything in our power to ensure our 107-year track record of water quality excellence continues.
Quarterly PFAS Test Results in detail
Frequently Asked Questions
PFAS: What are they?
PFAS, often referred to as forever chemicals are a group of thousands of manmade compounds – called per- and polyfluoroalkyl substances – that have been in use since the 1940s in common household and commercial products.
They are resistant to heat, stains, and water making them popular additions to cookware, clothing, carpets, cosmetics, and furniture. PFAS are also found in millions of other goods, including products you may have never imagined like dental floss, cake mix, cardboard straws, and toilet paper. The EPA estimates that 80% of a person’s exposure is from consumer products.
PFAS not only enters the environment through consumer use and disposal but also through surface and groundwater contamination. For example, PFAS proved to be an essential addition to firefighting foam. Unfortunately, for many communities near airbases and airports, the washing down of the foam after training exercises led to surface and groundwater contamination.
PFAS: How do these manmade compounds end up in drinking water?
Our water filtration plants do not produce or use PFAS. However, PFAS can end up in source water and then drinking water due to continued manufacturing and use of PFAS-laden products.
For example, PFAS are still used with nonstick cookware. Scraping and washing a nonstick pan with PFAS discharges the compounds into our wastewater system.
Because of their resistant properties, PFAS can move through the conventional water treatment processes largely intact.
PFAS: What is WSSC Water doing to supply safe, clean drinking water to customers?
WSSC Water’s mission is to protect public health and safety by supplying safe, clean and reliable water to our 1.9 million customers. We are proud of our 107-year history of zero drinking water quality violations and remain committed to continuing this exceptional level of excellence.
For several years, WSSC Water has been proactively testing for PFAS compounds in our drinking water, testing that went above and beyond federal and state requirements. WSSC Water monitors for 29 PFAS compounds that are included under the EPA’s Fifth Unregulated Contaminant Monitoring Rule, also known as UCMR5. We will continue to transparently post our results as we conduct our tests. PFAS Test Results
UMCR 5 testing is intended to give the EPA and water providers a greater understanding of how pervasive PFAS are in our nation’s drinking water. WSSC Water will review our UCMR5 test results to determine if additional courses of action are necessary.
PFAS: How to limit PFAS exposure?
Avoid buying non-stick cookware and stain-resistant furniture and carpeting containing PFAS. Look for ‘fluoro’ or ‘perfluoro’ in a list of ingredients or ask the manufacturer.
Limit eating foods packed in materials that use PFAS, like microwave popcorn bags, fast food boxes and bakery bags.
And avoid personal care products with PFAS, including certain dental floss, nail polish, facial moisturizers and cosmetics. Limiting the use of products containing PFAS will help protect drinking water supplies.
Related Links
WSSC Water is committed to providing you with safe, clean drinking water. Should you have any water quality concerns, please let us know by visiting our Report a Water Quality Complaint page.
In the News
- Most local water utilities already meet new EPA limits on 'forever chemicals' (WJLA)
- How will new federal limits on ‘forever chemicals’ in drinking water affect DC area? (WTOP)
May 2023 - Excerpt from WSSC Water Letter to EPA
"... we strongly urge EPA to consider altering its regulatory approach to regulate PFAS at the source, placing the burden of proof that the products are safe for consumers and the environment on those who manufacture and utilize PFAS products before they are manufactured."
Last Modified: April 18, 2025, 12:25 pm EDT