Greater Upper Marlboro Water Hardness & Quality Report (2026)

The water supply for Greater Upper Marlboro, Maryland, is managed by the Washington Suburban Sanitary Commission (WSSC Water), serving Prince George's County and surrounding areas in the Washington, D.C. metropolitan region. WSSC sources water from surface water and groundwater, including the Potomac River, Patuxent River, and local aquifers such as the Magothy and Patuxent formations. Treatment occurs at major facilities including the Patuxent and Potomac Water Filtration Plants, distributing to over 1.8 million residents across a 5,600 square mile service area.

The primary watershed encompasses the Potomac River Basin and Patuxent River Basin, with groundwater from Coastal Plain aquifers in Prince George's County. Key geological features include Potomac Group sediments — Cretaceous-age sands and clays of the Magothy Aquifer overlain by Quaternary unconsolidated deposits. These sedimentary layers, influenced by underlying limestone, impart a hard character through natural mineral leaching. Southern portions of the county, including Upper Marlboro, exhibit more pronounced mineralization due to limestone proximity.

Hard water in this area promotes scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan. White deposits appear on fixtures and kettles, while soap lathering is inhibited, increasing detergent use. Annual water heater flushing, vinegar descaling, and hard-water detergents help mitigate issues; a whole-home water softener is recommended for households with persistent scaling. WSSC Water maintains EPA compliance, with annual Consumer Confidence Reports confirming no lead or copper violations; treatment involves coagulation, filtration, chloramine disinfection, and corrosion control; pH typically 7.5–8.5.