Kingsport Water Hardness & Quality Report (2026)

Kingsport, Tennessee, the Sullivan County seat in the Tri-Cities region of northeast Tennessee — the 'Model City,' one of the first comprehensively planned cities in the United States (planned by John Nolen in 1916), home of Eastman Chemical Company (one of the largest chemical plants in North America), and the NASCAR Bristol Motor Speedway (nearby) — draws its municipal water supply from Patrick Henry Lake (South Fork Holston River, TVA reservoir) via the Kingsport Power Board Utilities Water Division. Water hardness in Kingsport measures 153.5 mg/L — classified as hard.

Kingsport's hard supply reflects the South Fork Holston River's northeast Tennessee Ridge and Valley calcareous geology. The South Fork Holston River above Patrick Henry Lake drains: the Ridge and Valley Province of northeast Tennessee — Cambrian–Ordovician calcareous carbonate formations (Knox Group dolomite, Conasauga Group limestone — the thickest Cambrian carbonate sequence in the Southern Appalachians, highly soluble calcareous formations); the Virginia–Tennessee border Valley (Ordovician Moccasin and Bays Formations calcareous limestone); and the Unaka Mountains (Proterozoic Unicoi and Hampton Formations — calcareous-poor basement terrain, but the valley carbonate formations dominate). The Ridge and Valley calcareous dolomite and limestone produce the hard 153.5 mg/L at Kingsport.

At 153.5 mg/L, Kingsport residents face regular hard water challenges. Scale deposits form on faucet aerators, showerheads, and appliances within weeks — monthly descaling with citric acid solution is standard maintenance. Kingsport Power Board Utilities Water Division consistently delivers water meeting all Tennessee TDEC and EPA Safe Drinking Water Act requirements.