Pico Rivera Water Hardness & Quality Report (2026)

The Pico Water District supplies groundwater to approximately 23,000 residents in Pico Rivera, Los Angeles County, California. All water is pumped from local wells in the Central Basin aquifer, with no surface water sources. The district maintains storage tanks and extensive mainlines serving metered connections throughout the service area. Regular testing complies with California Health and Safety Code standards, and annual Consumer Confidence Reports detail monitoring results.

The Central Basin spans the Los Angeles Basin, recharged by local rainfall, imported water, and urban runoff percolating through alluvial fans. The aquifer consists of Quaternary and Pleistocene sedimentary formations including the San Pedro and Silverado aquifers, with underlying marine shales and sandstones from the Monterey and Modelo Formations. Surrounding sedimentary rocks of the Puente and Fernando Formations, rich in limestone and dolomite, dissolve substantial calcium and magnesium into the groundwater, yielding a very hard supply at 293 mg/L with elevated total dissolved solids from semi-arid recharge and evaporative concentration.

Very hard water at 293 mg/L causes significant scale buildup in pipes, water heaters, dishwashers, washing machines, and coffee makers, while soap lathering diminishes and energy bills rise from mineral-insulated heating elements. Routine maintenance includes annual appliance descaling, vinegar soaks for showerheads, and professional pipe inspections; a water softener is strongly recommended for all households. Water pH ranges 7.1–7.7, with sodium at 56.5 mg/L and potassium at 4.5 mg/L. The supply meets EPA legal limits and California drinking water standards, though PFOS and PFOA notification levels were recently exceeded in PRWA groundwater (below response levels), and arsenic, chromium-6, and PFAS exceed independent health guidelines but not MCLs.