Hendersonville Water Hardness & Quality Report (2026)

Hendersonville, Tennessee, in Sumner County northeast of Nashville on Old Hickory Lake — a major Nashville suburb and one of the fastest-growing cities in the Nashville metropolitan area, known as the 'City by the Lake' for its Cumberland River lakefront community — draws its municipal water supply from Old Hickory Lake (Cumberland River) via the City of Hendersonville Water Utilities, treating Cumberland River reservoir water for the Hendersonville area. Water hardness in Hendersonville measures 104.5 mg/L — classified as moderately hard.

Hendersonville's moderate hardness reflects the Cumberland River's central Tennessee calcareous watershed. The Cumberland River above Old Hickory Lake drains: the Cumberland Plateau (Pennsylvanian–Mississippian calcareous sandstone and limestone of the Pottsville and Pennington Formations); the Highland Rim (Mississippian St. Louis Limestone and Warsaw Limestone — calcareous Mississippian carbonate formations of central Tennessee); and the Nashville Basin (Ordovician Lebanon Limestone and Carters Limestone — the core of the Nashville Dome Ordovician carbonate exposure). The Tennessee Valley Mississippian and Ordovician carbonates contribute moderate dissolved calcium to the Cumberland River, producing the moderate 104.5 mg/L at Hendersonville after reservoir dilution and treatment.

At 104.5 mg/L, Hendersonville residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. City of Hendersonville Water Utilities consistently delivers water meeting all Tennessee TDEC and EPA Safe Drinking Water Act requirements.