Waco Water Hardness & Quality Report (2026)

City of Waco Public Works Department provides drinking water to over 138,000 residents in McLennan County, Texas, primarily within Waco city limits and surrounding areas. Sources include Lake Waco on the Brazos River, managed by the U.S. Army Corps of Engineers, and groundwater from the Trinity Aquifer. Treatment occurs at the Lake Waco Water Treatment Plant, with possible supplemental facilities for groundwater blending, using conventional coagulation, sedimentation, filtration, and chlorination to meet federal and state drinking water standards.

The Brazos River watershed drains much of Central Texas, with Lake Waco impounded in a valley carved through Cretaceous limestone formations of the Trinity Group, including the Glen Rose and Walnut Clay members. The underlying Trinity Aquifer features karstic limestone and dolomite from the Lower Cretaceous, promoting mineral dissolution during recharge. This geology imparts a hard character to the water, with elevated calcium and magnesium from carbonate weathering, moderated somewhat by reservoir storage and mixing with aquifer sources.

At moderately hard levels, Waco's water promotes limescale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan; faucet aerators and showerheads may clog, affecting flow and pressure. Regular descaling with vinegar, installing drain screens, and flushing hot water heaters annually help mitigate these effects, and a water softener is recommended for households with noticeable scale or long-term appliance protection. The utility earned a C+ water quality score; treatment at the Lake Waco Water Treatment Plant involves coagulation, sedimentation, filtration, and chlorination, with compliance maintained for disinfection byproducts.