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DMV Water Pros

What is actually in DMV tap water

Every number below comes from the utility's own published reports, and each profile links to the source. Where we could not verify a figure directly, we say so. No scare tactics: the water is safe, and the details still matter for choosing equipment.

Enter your ZIP code to see your utility's reported hardness, disinfectant and source.

Municipal utilities

UtilityHardnessDisinfectantSource
Fairfax WaterVA5 to 10 grains per gallonChloraminePotomac River (Corbalis plant) and the Occoquan Reservoir (Griffith plant)
Arlington County WaterVA7 to 9 grains per gallonChloraminePotomac River, treated by the Washington Aqueduct (U.S. Army Corps of Engineers)
DC WaterDC4 to 7 grains per gallonChloraminePotomac River, treated by the Washington Aqueduct (Dalecarlia and McMillan plants)
Virginia American Water (Alexandria)VAabout 5 to 10 grains per gallonapprox.ChloramineTreated water purchased from Fairfax Water (Potomac and Occoquan sources)
Loudoun WaterVAabout 5 to 10 grains per gallonapprox.ChloraminePotomac River (Trap Rock plant) plus water purchased from Fairfax Water
Town of Leesburg UtilitiesVAabout 5 to 10 grains per gallonapprox.Not yet confirmedPotomac River, treated at the town-owned water treatment plant
Prince William WaterVAabout 5 to 10 grains per gallonapprox.ChloramineMostly treated water purchased from Fairfax Water (Occoquan), with some supply from the City of Manassas (Lake Manassas)
City of Manassas UtilitiesVAModerately hard (confirm)approx.Not yet confirmedLake Manassas (Broad Run), treated at the city-owned plant
WSSC WaterMDabout 4 to 8 grains per gallonapprox.Free chlorinePotomac River (Potomac plant) and the Patuxent reservoirs (Patuxent plant)
City of Rockville WaterMDabout 4 to 8 grains per gallonapprox.Not yet confirmedPotomac River, treated at the city-owned plant
Howard County Bureau of UtilitiesMDabout 3 to 7 grains per gallonapprox.Free chlorineTreated water purchased from Baltimore City and from WSSC Water
City of Frederick WaterMDabout 6 to 12 grains per gallonapprox.Not yet confirmedPotomac River, Monocacy River and local reservoirs (Fishing Creek and Linganore)

Wells and community systems

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