Germantown Water Hardness & Quality Report (2026)

Germantown, Maryland, a major planned community in northwest Montgomery County, receives its municipal water supply from the Washington Suburban Sanitary Commission (WSSC Water), sourcing from the Potomac River at the WSSC Potomac Water Filtration Plant (Little Falls, Montgomery County) — treating Potomac River water for delivery to Montgomery County and Prince George's County. The Potomac at Little Falls is the primary source for the WSSC northwest Montgomery County distribution system serving Germantown and surrounding communities. Water hardness measures 131 mg/L — classified as moderately hard.

Germantown's moderate hardness reflects the Potomac River's accumulated mineral load from its upper watershed. The Potomac River at Little Falls collects: Blue Ridge Province drainage (Catoctin Formation metabasalt, Weverton Quartzite — relatively soft) from the west; Appalachian Great Valley drainage (Ordovician Beekmantown and Frederick limestones, Silurian–Devonian calcareous formations — significant carbonate input from the limestone valley); and the Shenandoah River (a major Potomac tributary draining the Valley and Ridge carbonate belt in Virginia and West Virginia — very high calcium contribution). The combination of Great Valley and Valley and Ridge carbonate drainage makes the Potomac moderately hard by the Little Falls intake. WSSC's treatment process and the northwest Montgomery County distribution system produce consistent 131 mg/L in the Germantown zone.

With hardness at 131 mg/L, Germantown residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. Dishwashers produce cleaner glassware with rinse-aid. WSSC Water consistently delivers water meeting all Maryland MDE and EPA Safe Drinking Water Act requirements.