Largo Water Hardness & Quality Report (2026)

The Largo, Maryland area receives its water supply from WSSC Water, a major regional utility that serves Prince George's County and Montgomery County. WSSC Water draws from a variety of sources, including the Patuxent River and Potomac River systems. These raw water sources are processed at several treatment plants across the utility's extensive 1,000-square-mile service area, which supplies water to over 1.8 million residents. The utility's conventional treatment processes include coagulation, sedimentation, filtration, and chlorination to ensure the water is microbiologically safe and meets all federal and state drinking water standards.

The Largo area's geology is characteristic of the Atlantic Coastal Plain. The underground formations consist of Cretaceous-age sedimentary layers, specifically the Patapsco and Patuxent aquifer systems. These layers are composed of sand, silt, and clay, often interbedded with calcareous materials. Much of the surface water, particularly from the Patuxent River watershed, originates from terrain rich in limestone and other mineral-bearing rocks. This geological makeup naturally imbues the water with significant levels of dissolved minerals, such as calcium and magnesium, leading to the hard water conditions commonly found in Prince George's County.

Homeowners in Largo should anticipate the effects of hard water, which can include scale buildup on faucets and showerheads, and reduced lathering from soaps and detergents. Appliances like water heaters and dishwashers may also be affected over time by this mineral accumulation. To combat these issues, residents might consider installing point-of-use filters or a whole-home water softening system, especially if scaling becomes a persistent problem. Routine maintenance, such as descaling fixtures and flushing water heaters, is also advisable. WSSC Water reports its water quality annually, detailing compliance with the Safe Drinking Water Act and testing for regulated contaminants.