Evansville Water Hardness & Quality Report (2026)

Evansville, Indiana — a major Ohio River port city — draws its municipal water supply directly from the Ohio River via the City of Evansville Water and Sewer Division, operating an intake and treatment facility on the Ohio River in Vanderburgh County. Evansville's water treatment plant processes Ohio River water through conventional treatment before distribution. The Ohio River at Evansville represents an accumulation of drainage from the vast Ohio River basin — including tributaries from the Appalachian Mountains, the Kentucky and Indiana Interior Plateau, and the Illinois Basin. Water hardness measures 141.5 mg/L — classified as moderately hard.

Evansville's moderate hardness reflects the blended mineral character of Ohio River water at the lower Indiana reach. The Ohio River at Evansville collects drainage from: the Pennsylvanian Illinois Basin coal measures and carbonate formations via the Green River (Kentucky); the Mississippian Indiana Interior Plateau limestone (Salem Limestone, St. Louis Limestone, Warsaw Formation) via the Wabash River; the Devonian Kentucky and Ohio limestone formations via the Blue Grass and Cumberland tributaries; and the Appalachian Mountains via the Big Sandy, Kanawha, and other tributaries (contributing more dilute, acidic mountain runoff). The blended result is moderately hard supply, as the calcareous Interior Plateau tributaries dominate over the softer Appalachian fraction at this lower Ohio reach.

At 141.5 mg/L, Evansville residents encounter moderate scale accumulation over time. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is a practical routine. Dishwashers produce better glassware results with rinse-aid, and water heaters benefit from annual inspection for element scale. City of Evansville Water and Sewer Division consistently delivers water meeting all Indiana DEM and EPA Safe Drinking Water Act requirements.