Sylmar Water Hardness & Quality Report (2026)

The Los Angeles Department of Water and Power (LADWP) provides water to Sylmar, California, in the northern San Fernando Valley of Los Angeles County. Sources include local groundwater from the Sylmar and San Fernando groundwater basins, supplemented by imported surface water via the Los Angeles Aqueduct from Owens Valley reservoirs and the Metropolitan Water District's (MWD) California Aqueduct from the State Water Project. Treatment occurs at facilities including the Jensen and Griffith Water Treatment Plants, serving over 4 million people across 465 square miles.

Local groundwater draws from the Sylmar Alluvial Basin, featuring Quaternary sands and gravels over Pliocene-Miocene sedimentary formations, with limestone and dolomite outcrops in the surrounding San Gabriel Mountains contributing dissolved calcium and magnesium. Imported water originates from the Owens Valley watershed and Sierra Nevada snowmelt, blended with local San Fernando Valley basin recharge from the Santa Clara River and Pacoima Wash. This mineral-rich geology — especially carbonate dissolution under arid low-rainfall conditions — produces a hard supply prone to elevated calcium and magnesium concentrations.

Very hard water in Sylmar promotes significant scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency, shortening appliance life, and raising energy costs. Soap lathering is poor, leaving residue on skin, hair, and laundry. Regular descaling of fixtures, vinegar soaks for showerheads, and water softeners — strongly recommended for very hard water — help prevent clogs and extend plumbing lifespan. LADWP reports pH typically 7.5–8.5, compliant with EPA standards; the system meets lead and copper rules via corrosion control. PFAS levels are below California notification levels post-treatment; notable contaminants include low levels of hexavalent chromium and nitrates from agricultural runoff, addressed by filtration, chloramination, and blending.