What's in your area's water?

Washington, DC tap water is treated by DC Water using the Washington Aqueduct's Potomac River source. It meets federal legal limits, but EWG testing flags several disinfection byproducts and other contaminants well above health-based guidelines.

Arlington County buys finished water from the Washington Aqueduct, so its contaminant profile mirrors DC's. Chlorination byproducts and hexavalent chromium are the contaminants that most exceed EWG health guidelines.

Alexandria's water (Virginia American Water) is drawn from the Potomac and shares the region's disinfection-byproduct profile, with PFAS and chromium-6 also detected above EWG health guidelines.

Fairfax Water treats Potomac River and Occoquan Reservoir water at its own plants. Nine contaminants, led by hexavalent chromium and disinfection byproducts, exceed EWG health guidelines here.

Montgomery County (including Bethesda) is served by WSSC Water from the Potomac and Patuxent rivers. Its trihalomethane and haloacetic-acid averages sit hundreds of times above EWG's health-based guidelines.

Silver Spring is served by WSSC Water, drawing from the Potomac and Patuxent rivers. Chlorination byproducts (trihalomethanes and haloacetic acids) are the contaminants that most exceed EWG's health-based guidelines here.

Rockville's tap water comes from WSSC Water. While fully EPA-compliant, its disinfection-byproduct and hexavalent-chromium levels sit well above EWG's stricter health guidelines.

Reston is served by Fairfax Water from the Potomac River and Occoquan Reservoir. Hexavalent chromium and chlorination byproducts are the contaminants most above EWG's health guidelines.

McLean's water is treated by Fairfax Water. It meets federal limits, but EWG testing flags nine contaminants, led by chromium-6 and disinfection byproducts, above health-based guidelines.

Vienna is served by Fairfax Water from the Potomac and Occoquan sources. Its supply carries hexavalent chromium and chlorination byproducts above EWG's stricter health guidelines.