Harmful Algal Bloom Advisory

Triadelphia Reservoir

Difficulty Paying Your Bill?

Financial Assistance Available


To deliver the safest water possible, WSSC Water goes above and beyond federal guidelines by testing for the chemical compounds known as PFAS.

Is WSSC Water Safe?
Yes! For more than 102 years, our water has consistently met all strict federal Safe Drinking Water Act requirements. In fact, we have never had a single drinking water quality violation in our history.

PFAS: What are they?

PFAS - Per- and Polyfluoroalkyl Substances - are man-made chemicals that were developed in the 1940s to be resistant to fire, oil, grease, water and stains. The chemicals are found in a wide range of consumer and industrial products, including non-stick cookware, stain repellants, dental floss, cleaning products and cosmetics. The Centers for Disease Control and Prevention says the potential adverse health effects of PFAS in humans is not yet well understood.

How do these compounds get in the environment?

The chemicals commonly enter the environment as discharges from PFAS manufacturing and processing facilities, and from facilities that use the product in large quantities, such as airports and military installations. Two of the most common compounds - PFOA and PFOS - have been the most extensively produced chemicals and are very persistent in the human body and environment, which means they accumulate over time and don’t break down. Once they enter the environment and source water, PFAS compounds cannot be removed by the water treatment process. Fortunately, the number of contaminated sites in Maryland is very small, and no known PFAS-contaminated sites are upstream of our drinking water sources. The Maryland Department of the Environment assesses potential PFAS contamination sources to keep WSSC Water informed of possible future risks.

How much is too much?

The EPA does not regulate PFAS compounds but maintains a health advisory of 70 parts per trillion (ppt) for two of the most common compounds: PFOA and PFOS; currently, this is the only federal health standard. One part per trillion is equivalent to one drop of water in 20 Olympic-sized swimming pools. Some states independently regulate, or propose to regulate, more PFAS compounds using more stringent standards. This is due to higher levels of PFAS in their drinking water and the presence of contaminated sites in their drinking water sources. WSSC Water continues to closely monitor the possible need for federal PFAS testing and is ready to test for these compounds should it be required by the Environmental Protection Agency.

What is WSSC Water doing about PFAS?

In early 2020, we resumed testing of water from both of our filtration plants. Testing during the first quarter of the year confirmed that the water we deliver to Montgomery and Prince George's County homes and businesses is safe from PFAS contamination. Only two compounds (Perfluorohexanoic acid and Perfluorooctanoic acid) were detected, at levels barely above the minimum reporting level of 1.8 parts per trillion - well below the EPA's health advisory level of 70 ppt.


WSSC Water tests quarterly for 18 different PFAS compounds using new analytical methods developed and approved by EPA.

Questions about PFAS?

Call us if you have additional questions about PFAS or water quality: 301-206-4002.

See if your question is answered in the PFAS Fact Sheet

WSSC Water has an aggressive water quality testing program – performing 500,000 laboratory tests per year on samples collected at both water filtration plants and 90 different locations throughout its service area.

Current PFAS Test Results

WSSC Water resumed PFAS testing in January 2020. In making the announcement to resume testing, WSSC Water General Manager and CEO Carla A. Reid strongly encouraged continued federal and state action to protect drinking water supplies.

View our Latest PFAS Test Results

Historical PFAS Results

WSSC Water conducted extensive water quality testing for six PFAS compounds in 2013-2014 and again from 2015 through 2017 and found results below EPA detection limits.  

View the 2013 - 2017 Test Result charts

Last Modified: July 13, 2022, 4:08 pm EDT