Moraga Water Hardness & Quality Report (2026)

East Bay Municipal Utility District (EBMUD) provides water to Moraga, California, in Contra Costa County, serving over 1.4 million people across 20 cities in the East Bay region. The primary source is surface water from the Mokelumne River via Pardee Reservoir and the Mokelumne Aqueducts, delivering about 80% of supply. The remaining 20% comes from three local reservoirs: Upper San Leandro, Lake Chabot, and San Pablo. Water is treated at the El Cerrito Treatment Plant, Sobrante Treatment Plant, and Bay Division Pipeline facilities before distribution.

The Mokelumne Watershed spans 1,400 square miles in the Sierra Nevada, flowing through granitic and metavolcanic rocks of the Paleozoic Calaveras Complex and Mesozoic Franciscan Formation, including greenstone and serpentinite. Local reservoirs draw from East Bay streams draining Franciscan Complex mélange and sedimentary basins of the Diablo Range — serpentine, sandstone, and shale — imparting a moderately mineralised character to raw water. EBMUD's treatment blending of high- and low-mineral sources results in characteristically soft water delivered to the service area.

At soft water levels, Moraga residents experience minimal scaling on fixtures, pipes, or appliances — no buildup on faucets, showerheads, or water heaters. Soap lathers easily, reducing detergent use, and laundry feels softer without fabric stiffening. No water softener is needed; however, overly soft water may slightly corrode older galvanized pipes. Recent EBMUD data shows pH around 9.0, within optimal range. The utility complies fully with EPA lead and copper rules with no action level exceedances. Treatment includes ozonation, filtration, chloramination, and corrosion control; no PFAS detections above limits per 2026 testing.