Twin Falls Water Hardness & Quality Report (2026)

Twin Falls, Idaho, the Twin Falls County seat on the Snake River at Shoshone Falls — the 'Visitor Capital of Idaho,' gateway to the Snake River Canyon (Shoshone Falls, the 'Niagara of the West'), Perrine Bridge, and the Buzz Aldrin/Evel Knievel jump site, a major Magic Valley agricultural and dairy processing hub (Chobani's largest yogurt plant in the world is in Twin Falls) — draws its municipal water supply from the Snake River Plain Basalt Aquifer springs and the Twin Falls Canal Company Snake River diversion via the City of Twin Falls Public Works Water Division. Water hardness in Twin Falls measures 106.5 mg/L — classified as moderately hard.

Twin Falls' moderate hardness reflects the Snake River Plain's calcareous volcanic and alluvial geology. The Snake River Plain Basalt Aquifer (the massive Quaternary Snake River Plain basalts — lava flows with excellent porosity) is recharged primarily from the upstream Snake River irrigation infiltration and Big Lost and Little Lost River sinks (calcareous loss streams from the Lost River Range limestone terrain — calcareous Lost River Range Paleozoic carbonate recharge). The Thousand Springs (the natural discharge of the Snake River Plain Aquifer at the canyon walls) supply the Twin Falls area with moderately calcareous spring water, producing the moderate 106.5 mg/L at Twin Falls.

At 106.5 mg/L, Twin Falls 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 Twin Falls Public Works Water Division consistently delivers water meeting all Idaho DEQ and EPA Safe Drinking Water Act requirements.