College Park Water Hardness & Quality Report (2026)

Washington Suburban Sanitary Commission (WSSC Water) provides water to College Park, Maryland, in Prince George's County, serving over 1.8 million residents across Montgomery and Prince George's counties. Primary sources include the Potomac River (70%) via the Washington Aqueduct and Patuxent River (30%) from the Brighton Dam Reservoir. Treatment occurs at the Patuxent Water Filtration Plant and Potomac Water Filtration Plant, with distribution through an extensive pipeline network covering the Washington, DC suburbs.

The Potomac and Patuxent watersheds span the Appalachian Piedmont and Coastal Plain, with limestone and dolomite in upstream Appalachian plateaus transitioning to sandy Cretaceous sediments downstream. The Piedmont's metamorphic and igneous rocks yield moderately mineralized runoff, while Coastal Plain aquifers like the Patapsco Formation (sandstones and clays) add dissolved ions from shell fragments and calcareous sands. The Patuxent Formation (unconsolidated sands and gravels) also contributes to the hard character of the supply through mineral dissolution during river flow and groundwater recharge across the Piedmont-Coastal Plain transition zone.

Hard water in this area promotes scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan. White deposits on fixtures and soap scum are common, increasing detergent use and cleaning needs. Regular vinegar descaling, installing scale inhibitors, or a water softener is recommended to mitigate effects and protect appliances. WSSC Water reports consistent compliance with EPA standards, including zero violations over 108 years, with pH typically 7.2–8.0; lead and copper levels meet action levels through corrosion control; treatment includes coagulation, sedimentation, filtration, chloramination, and fluoride addition, with occasional manganese or iron detections addressed via advanced oxidation.