West Valley Water Hardness & Quality Report (2026)

The West Valley Water District serves approximately 75,000 residents in parts of Rialto, Fontana, and Colton, California, drawing water from multiple sources. Their supply includes imported water from the Metropolitan Water District of Southern California, local groundwater from the Rialto-Colton Basin aquifers, and allocations from the State Water Project. Water undergoes treatment at facilities like the Geer Creek Water Treatment Plant, with additional supply coming from numerous groundwater wells. The WVWD consistently meets all Environmental Protection Agency standards, with detailed reports available on their website.

The watershed relies on the upper Santa Ana River basin and the Rialto-Colton groundwater subbasin. This area's geology is a mix of Quaternary alluvium, Pleistocene lakebed deposits, and underlying Franciscan Complex bedrock. Recharge comes from infrequent rainfall and imported surface water. The local aquifers are primarily composed of granitic and sedimentary formations, which contribute very little mineral leaching, resulting in a generally soft water character. However, blending with harder imported supplies can slightly increase mineralization depending on the season and allocation.

Homeowners in areas served by WVWD typically experience minimal issues related to water hardness. You'll find little to no scale buildup on fixtures or reduced efficiency in appliances like dishwashers and water heaters. Soap and detergent perform optimally, creating suds without excessive lathering. The longevity of plumbing is generally enhanced due to the absence of mineral deposits. A water softener isn't usually necessary; instead, homeowners might consider corrosion prevention methods if the pH is on the lower side. WVWD also ensures compliance with lead and copper regulations and treats for contaminants like arsenic from groundwater, maintaining a pH between 7.5 and 8.5.