Covina Water Hardness & Quality Report (2026)

The City of Covina, California, receives drinking water from two primary sources: the Covina Irrigating Company (CIC), which operates surface water treatment from the San Gabriel River, and the Metropolitan Water District of Southern California (MWD). During February, July, and August, MWD supplies imported surface water originating from the Colorado River and the Sacramento–San Joaquin river systems in Northern California, delivered through the Weymouth Plant. The city routinely tests its distribution system for bacterial and chemical contaminants and maintains compliance with EPA drinking water standards, with zero EPA violations reported since 2023.

The San Gabriel River watershed drains the San Gabriel Mountains and flows through the Los Angeles Basin, underlain by Quaternary alluvial deposits overlying older Tertiary sediments. These formations contain significant concentrations of dissolved minerals, particularly calcium and magnesium compounds leached from natural deposits. The imported MWD supply, drawn from the Colorado River and Northern California's major river systems, similarly carries mineral-rich water, and this combination of local and imported sources results in a hard water supply.

At this hard water level, residents can expect noticeable scale buildup on fixtures, reduced soap lathering, and potential dry skin after bathing. Water heaters, dishwashers, and washing machines are particularly vulnerable to mineral accumulation, which reduces efficiency and can shorten appliance lifespan. Pipes may gradually clog with scale deposits. A water softener is strongly recommended to mitigate these effects. Tap water meets all EPA legal drinking water standards; the 2024 Consumer Confidence Report confirms disinfection with chlorine or chloramines and lead levels at 0 mg/L.