DeSoto Water Hardness & Quality Report (2026)

The City of DeSoto Public Utilities Department serves approximately 53,000 residents in DeSoto, Texas, located in Dallas County. Drinking water is sourced from six reservoirs — Grapevine, Lewisville, Ray Roberts, Ray Hubbard, Fork, and Tawakoni — as well as the Elm Fork of the Trinity River. Ray Hubbard is fully owned and operated by the City of Dallas. Water is treated using settling, filtration, chemical addition, and ozone disinfection before distribution to customers.

The supply originates in the Trinity River Basin, where Cretaceous-age formations including the Woodbine and Trinity Group sandstones and limestones shape regional hydrology. Karstic Fredericksburg and Washita Group limestone and dolomite layers — characteristic of the Edwards Plateau fringe — dissolve calcium and magnesium into reservoir inflows. Gulf Coastal Plain clay and silt layers further moderate flow while reinforcing the mineralised profile, resulting in a hard supply with elevated mineral content typical of Central Texas surface waters.

At this hard level, scale buildup is prominent in pipes, water heaters, fixtures, dishwashers, and washing machines, reducing efficiency and increasing energy costs. Laundry may appear dingy and skin can feel dry after bathing. Regular vinegar descaling, low-flow aerators, and scale-inhibiting filters help mitigate these effects; a whole-house water softener is recommended to extend appliance life and improve soap efficiency. Treatment includes chloramine and ozone disinfection, lime and iron sulfate for solids removal and corrosion control, activated carbon for taste and odor, and fluoride addition. Third-party assessments note exceedance of health guidelines for 1,2,3-Trichloropropane (TCP) from soil fumigants, though the utility meets all legal compliance standards; monitoring for organic contaminants is advised.