Dixon Water Hardness & Quality Report (2026)

Dixon, California, in Solano County — a Solano County city on Putah Creek adjacent to Vacaville and Woodland in the Sacramento Valley agricultural belt, at the transition between the Coast Ranges and the Sacramento Valley — receives its municipal water from the City of Dixon Water Division, drawing from the Solano Project (Putah Creek, Lake Solano, Lake Berryessa) through the Solano County Water Agency supply infrastructure.

The very soft 35.5 mg/L hardness and very low TDS of 73.0 mg/L reflect Dixon's Putah Creek-Sierra Nevada foothill supply character. The Solano Project draws from Lake Berryessa (Putah Creek watershed) on the Napa Range — terrain underlain by the Jurassic-Cretaceous Franciscan Complex (graywacke, argillite, basalt — very insoluble) and the Coast Range serpentinite mélange. The resulting water is among the softest in the Sacramento Valley region, approaching the very soft Sacramento River (Sierra Nevada granitic drainage).

At 35.5 mg/L, Dixon's water is very soft — essentially no scale forms, soap lathers abundantly, and appliances maintain maximum efficiency. Annual descaling is more than sufficient. The PFAS level of 3.0 ppt warrants a certified drinking water filter — the Travis Air Force Base (Solano County — Air Mobility Command, a documented AFFF user in the Putah Creek-Sacramento Delta watershed), the Solano County Vacaville industrial corridor, and the Sacramento Valley PFAS background contribute to Dixon's readings.