Dixon Water Hardness & Quality Report (2026)

California Water Service Company (Cal Water) provides drinking water to the City of Dixon in Solano County, California, serving approximately 20,000 residents across a 15-square-mile area. The utility sources all water from local groundwater wells tapping into the Sacramento Valley aquifers, with no surface water imports. Key facilities include multiple production wells such as Dixon Wells 1–6, with a treatment plant employing chloramination for disinfection, blending, and corrosion control. The system is regulated by the California State Water Resources Control Board and complies with federal Safe Drinking Water Act standards.

The Sacramento Valley groundwater basin, bounded by the Sierra Nevada to the east and the Coast Ranges to the west, forms the supply's watershed. Water percolates through Quaternary alluvial deposits of sand and gravel interbedded with clay lenses from ancestral Sacramento River channels, overlying the Mehrten Formation (Pliocene-Pleistocene). Limestone and dolomite clasts in the aquifer matrix, derived from eroded Sierra Nevada granitic and volcanic rocks, leach calcium and magnesium during prolonged groundwater residence, producing a characteristically hard supply without softening influences.

At 215 mg/L (hard), limescale buildup is heavy in pipes, water heaters, dishwashers, and fixtures, reducing efficiency by up to 20–30%. Kettles, coffee makers, and washing machines suffer spotting and clogging most acutely. Regular vinegar descaling, magnetic conditioners, or template-assisted crystallization can mitigate effects; a whole-house water softener is strongly recommended. Water quality shows pH typically 7.5–8.2, with full lead and copper rule compliance (90th percentile copper <1.0 mg/L). Nitrate averages 5.0 ppm, well below the 10 ppm MCL; no PFAS detections above lab limits in recent CCRs. Fluoride is adjusted to 0.7 ppm.