Tulare Water Hardness & Quality Report (2026)

Tulare, California, in Tulare County on the southern San Joaquin Valley floor — one of California's most productive dairy and agriculture counties, historically the site of Tulare Lake (once the largest freshwater lake in the United States west of the Mississippi) — draws its municipal water supply from Kings River and Kaweah River diversions and local Tulare Basin groundwater wells via the City of Tulare Public Works Water Division, accessing the Kings–Kaweah alluvial fan aquifer system of the southern San Joaquin Valley. Water hardness in Tulare measures 110.5 mg/L — classified as moderately hard.

Tulare's moderate hardness reflects the Tulare Basin's mixed Sierra Nevada alluvial fan and groundwater geology. The Kings River and Kaweah River originate in the southern Sierra Nevada (Sequoia–Kings Canyon granite and granodiorite terrain — calcium-poor at source). However, by the time the Kings and Kaweah Rivers reach the Tulare Basin floor, their alluvial fans have deposited calcareous gravel and the San Joaquin Valley groundwater has substantial dissolved calcium from evaporative concentration in the semi-arid valley floor. The local Tulare Basin groundwater (from the Tulare Formation — Pliocene calcareous non-marine sediment deposited in the ancient Tulare Lake basin) contributes moderate dissolved calcium. The resulting blend at Tulare produces the moderate 110.5 mg/L supply.

At 110.5 mg/L, Tulare 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 Tulare Public Works Water Division consistently delivers water meeting all California SWRCB and EPA Safe Drinking Water Act requirements.