Ventura Water Hardness & Quality Report (2026)

City of Ventura Public Works Department manages drinking water for approximately 110,000 residents across West, Midtown, and East Ventura, Ventura County, California. Primary sources include surface water from the Ventura River (groundwater under the influence of surface water near Foster Park), treated surface water purchased from Lake Casitas via Casitas Municipal Water District, and groundwater pumped from the Mound, Oxnard Plain, and Santa Paula basins. Water is treated at the Foster Park plant for river water and at blending stations integrating groundwater supplies, serving residential, commercial, and industrial users across this coastal Southern California city.

The supply originates in the Ventura River watershed, spanning the Transverse Ranges and draining toward the Pacific. Lake Casitas captures runoff from granitic and sedimentary highlands. The Mound, Oxnard Plain, and Santa Paula basins are coastal alluvial aquifers recharged by river infiltration, rainfall, and imported state water. Regional geology features Cenozoic sedimentary rocks including the Monterey Formation (Miocene siliceous shales and carbonates), Pico and Repetto Formations, and overlying Quaternary alluvium — all rich in limestone, dolomite, and evaporitic deposits — imparting a characteristically hard supply through natural mineral dissolution during percolation and storage.

Very hard water in Ventura promotes significant scale buildup in pipes, heaters, fixtures, dishwashers, washing machines, and coffee makers, where mineral deposits insulate heating elements and clog valves, increasing energy costs by up to 50%. Annual flushing of water heaters, scale-inhibiting filters on faucets, and vinegar soaks for visible deposits are recommended. Water softeners are strongly recommended for households to extend appliance life and improve soap lathering while reducing skin and hair dryness. The 2023 Consumer Confidence Report confirms compliance with pH (typically 7.5–8.5), lead, copper, and PFAS standards; treatment includes coagulation, filtration, chlorine disinfection, and fluoridation.