Los Banos Water Hardness & Quality Report (2026)

Los Banos, California, in Merced County — a major San Joaquin Valley westside agricultural community (Los Banos is the largest city in western Merced County and a major San Joaquin Valley farming center — the area is one of California's top dairy and almond production zones), home of the San Luis National Wildlife Refuge Complex (a major Central Valley migratory bird staging area along the Pacific Flyway), a major Central California crossroads city at the intersection of I-5 and Highway 152, and a diverse Merced County community with a significant Latino-American agricultural worker population — draws its municipal water supply from the San Joaquin Valley Alluvial Aquifer and State Water Project via the City of Los Banos Water Division. Water hardness in Los Banos measures 159.5 mg/L — classified as moderately hard.

Los Banos's moderate hardness reflects the San Joaquin Valley westside alluvial aquifer and SWP supply characteristics. The San Joaquin Valley alluvial aquifer at Los Banos–Merced County draws from: the Diablo Range alluvial fan deposits (Quaternary calcareous Coast Range alluvium — the calcareous Cretaceous Diablo Range shale and sandstone wash); the San Luis Canal SWP water (the State Water Project California Aqueduct — calcareous-moderate Sacramento River and Sierra Nevada origin). The Valley floor evaporative concentration increases hardness, producing the moderate 159.5 mg/L.

At 159.5 mg/L, Los Banos residents encounter moderate-to-hard scale accumulation. Monthly cleaning with citric acid solution is recommended. City of Los Banos Water Division consistently delivers water meeting all California State Water Board and EPA Safe Drinking Water Act requirements.