Los Banos Water Hardness & Quality Report (2026)

The City of Los Banos Municipal Water Company serves approximately 37,766 residents in Los Banos, California, located in Merced County. Water is sourced entirely from thirteen city-owned groundwater production wells within the local aquifer system — there are no surface water reservoirs, rivers, or named treatment plants; the supply depends entirely on well extraction to maintain pressure and volume across the service area. The utility can be contacted at 209-827-7000 or 520 J Street, Los Banos, CA 93635.

The groundwater originates in the Westside Subbasin of the San Joaquin Valley Groundwater Basin, influenced by the adjacent Coastal Range geology. Ultramafic rocks and serpentinites of the Mesozoic Franciscan Complex release naturally occurring hexavalent chromium (chromium-6) as water flows through mineral-rich fractures and alluvium. This hard supply acquires high levels of calcium, magnesium, bicarbonate, and sodium from leaching natural deposits, creating a highly mineralized character without industrial influence — confirmed by city-commissioned studies.

Very hard water promotes significant scale buildup in pipes, water heaters, dishwashers, washing machines, and coffee makers, reducing efficiency and lifespan; soap lathering is poor, increasing detergent use and causing spotted dishes. Maintenance includes regular descaling of appliances, installing drain screens, and flushing water heaters annually; a water softener is strongly recommended to mitigate staining on fixtures, dry skin, and appliance damage. The 2020 Consumer Confidence Report confirms compliance with primary EPA and state MCLs; however, hexavalent chromium exceeds the new 10 ppb state limit (naturally occurring; compliance deadline October 2026), with additional concerns including nitrate and TTHMs per public notices.