Flower Mound Water Hardness & Quality Report (2026)

The Town of Flower Mound Public Works Department manages the water utility for the town in Denton and Tarrant Counties, Texas, serving approximately 80,000 residents across 43 square miles. Water is sourced exclusively from surface reservoirs, primarily Lake Lewisville with additional supply from Lake Ray Roberts. The utility purchases treated water from the Upper Trinity Regional Water District (UTRWD), which operates treatment plants drawing from these lakes. All water undergoes conventional treatment including coagulation, sedimentation, filtration, and disinfection before distribution to residents.

The reservoirs sit within the broader Trinity River Basin watershed, underlain by Cretaceous-era limestone and chalk formations including the Austin Chalk prevalent in North Texas. These carbonate-rich rocks contribute dissolved minerals to the surface waters feeding the lakes, creating a naturally hard supply. The geology of limestone aquifers and riverbeds throughout the region leads to elevated concentrations of calcium and magnesium, shaping the water's mineralized profile without additional softening applied during treatment.

Very hard water in Flower Mound promotes significant scale buildup in pipes, reducing flow efficiency and raising pressure that can cause leaks or bursts. Water heaters, dishwashers, and washing machines are most impacted, with reduced lifespan and higher energy costs from mineral encrustation. Regular descaling and flushing heaters is advised; a whole-home water softener using ion exchange is strongly recommended to protect plumbing infrastructure. The 2024 Annual Water Quality Report confirms EPA compliance; total trihalomethanes reached a maximum of 16.73 ppb (below the 80 ppb MCL) and fluoride was added at 0.602 mg/L. Water is safe to drink despite its very hard nature.