Sylmar Water Hardness & Quality Report (2026)

Sylmar, California — an LADWP-served neighborhood at the northernmost tip of the San Fernando Valley, adjacent to San Fernando city and the Santa Susana Mountains (home of the Sylmar Converter Station, a key LADWP transmission hub) — draws its municipal water supply from the Los Angeles Department of Water and Power (LADWP), sourcing from the LADWP blend of Los Angeles Aqueduct (Owens Valley and Mono Basin), State Water Project (SWP) imports, and the San Fernando Valley Groundwater Basin wells in the north Valley area. Water hardness in Sylmar measures 85 mg/L — classified as moderately soft.

Sylmar's moderately soft supply reflects the northwest San Fernando Valley LADWP distribution zone's characteristics. The LADWP primary supply (Owens Valley aqueduct — very soft; SWP — moderately soft) maintains the soft baseline, while local San Fernando Valley Groundwater Basin wells in the Sylmar–Mission Hills area tap the northern alluvial basin recharged by the Santa Clara River and Los Angeles River headwaters from the Transverse Ranges. The San Gabriel and San Fernando Valley groundwater in the north Valley tends toward softer character than the deep eastern Valley wells, reflecting recharge from the soft San Gabriel Mountains granodiorite runoff and Sierra Pelona Schist drainage. The 85 mg/L reading is consistent with north Valley LADWP service.

With hardness at 85 mg/L, Sylmar residents enjoy moderately soft water with minimal scale challenges. Faucet aerators and showerheads develop deposits slowly. LADWP consistently delivers water meeting all California SWRCB and EPA Safe Drinking Water Act requirements.