Duncanville Water Hardness & Quality Report (2026)

The City of Duncanville Water Utilities manages drinking water for Dallas County, Texas, serving approximately 40,000 residents. Water is purchased from the City of Dallas Water Utilities, drawn from seven surface water supplies: the Elm Fork of the Trinity River and Lakes Grapevine, Lewisville, Ray Roberts, Ray Hubbard, Fork, and Tawakoni. Treatment occurs at Dallas facilities using settling, filtration, ozone disinfection, chloramine, lime and iron sulfate for corrosion control, and activated carbon for taste and odor. The system maintains a 'Superior' water quality rating.

The Trinity River watershed drains a large area of North Texas, encompassing urban, agricultural, and natural lands that influence water chemistry. While surface-sourced, the supply interacts with regional geology featuring Cretaceous limestone and dolomite formations, along with gypsum deposits, which dissolve minerals into rivers and reservoirs fed by groundwater inflows. This results in a hard supply character with elevated calcium and magnesium from rock weathering and sediment interactions — no aquifer is directly used due to poor groundwater quality in the Dallas-Fort Worth area.

Very hard water leads to significant scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan while increasing energy costs. Soap lathering is poor, leaving scum and film on skin and dishes. Regular descaling of appliances, drain strainer installation, and vinegar soaks for fixtures are advised; a water softener is strongly recommended. The 2021 Consumer Confidence Report confirms compliance with federal standards, including nitrate at 0.33–0.452 ppm; third-party tests note 1,2,3-Trichloropropane above health guidelines from soil fumigants, though overall quality meets EPA/SDWA standards. Treatment includes chloramine and ozone disinfection, fluoride addition, and corrosion controls.