Kerrville Water Hardness & Quality Report (2026)

Kerrville, Texas, in Kerr County in the Texas Hill Country on the Guadalupe River in the heart of the Edwards Plateau — a popular retirement and vacation community known for its scenic river, Hill Country arts culture, and Kerrville Folk Festival — receives its municipal water from the Kerrville Public Utility Board, drawing from the Guadalupe River and the Trinity Aquifer — two quintessentially hard-water sources on the Cretaceous Edwards Plateau. The Guadalupe River originates from the Edwards Plateau springs and flows through pure limestone and dolomite terrain throughout Kerr County.

The extreme 412.5 mg/L hardness and extraordinary TDS of 1,283.8 mg/L represent one of the most severe hard water profiles in the entire USA dataset, reflecting the Edwards Plateau's uniquely massive Cretaceous carbonate geology. The Edwards Group on the Kerrville area Edwards Plateau is composed of the Lower Cretaceous Edwards Formation, Georgetown Formation, and related units — thousands of feet of nearly pure limestone, chalky dolomite, and reef-derived carbonate deposited in the warm Cretaceous interior seaway. The Trinity Aquifer additionally accesses older Cretaceous Glen Rose Formation (wavy-bedded limestone and dolomite) at depth. Water dissolving through this exceptionally thick, pure carbonate sequence produces hardness and TDS values at the extreme end of municipal water systems nationwide.

At 412.5 mg/L and TDS of 1,284 mg/L, Kerrville's water represents one of Texas's most extreme hard water communities. Scale forms immediately on all heated water surfaces within hours, dishwashers produce severely scaled glassware without aggressive water softener treatment, and the mineral character of unfiltered tap water is pronounced and generally unpalatable for drinking. A whole-house water softener is effectively mandatory for Kerrville households, and reverse osmosis for drinking water is the universal standard among residents. The PFAS level of 11.8 ppt — the highest in this batch — adds critical urgency: a certified reverse osmosis system addresses both the extreme mineral content and the PFAS contamination from the Kerr County military training and ranching land uses in a single treatment step.