Lexington Park Water Hardness & Quality Report (2026)

St. Mary’s County Metropolitan Commission (also known as MetCom) provides the drinking water for Lexington Park, drawing exclusively from groundwater. Nineteen wells tap into the Aquia, Piney Point, and Patapsco aquifers, which are confined sandstone formations. The water undergoes disinfection with hypochlorite at wellhead facilities; there are no surface water treatment plants. MetCom maintains a quality score of 80/100, with the supply originating from these deep aquifers, offering protection from surface contamination and land-based pollutants. This geological setup means the water's chemistry is naturally influenced by the surrounding rock.

The Aquia, Piney Point, and Patapsco formations are characterized by sandstone, limestone, and calcareous materials. Groundwater percolating through these Cretaceous-era strata dissolves minerals, particularly calcium and magnesium carbonates. This natural leaching process imbues the water with a hard character, affecting its taste and potential for mineral buildup. The confined nature of these aquifers means they are less susceptible to immediate surface runoff contamination, but the geology itself dictates the water's mineral content before it even reaches the treatment stage.

Homeowners in Lexington Park may notice mineral deposits forming scale in pipes over time, which can reduce water flow and impact the efficiency of appliances like water heaters and dishwashers, potentially shortening their lifespan. Faucet aerators and showerheads can also become clogged. To combat this, annual descaling of appliances, installing scale filters, or a whole-house water softener are recommended. While the MetCom supply complies with health guidelines, there's a note about potential naturally occurring arsenic in some Aquia wells, though no violations have been reported. Specific details on pH, lead/copper, and PFAS levels are best found in the utility's annual Consumer Confidence Report.