Everett Water Hardness & Quality Report (2026)

Everett, Washington — the largest city north of Seattle in Snohomish County — draws its municipal water supply from Spada Lake — a reservoir on the Sultan River in the Cascade Range of Snohomish County — operated by the Everett Public Works Water Division. Spada Lake is a major protected water supply reservoir serving Everett and portions of Snohomish County. The Sultan River originates in the central Cascades and flows through the Index Batholith granite terrain before reaching the Skykomish Valley. Water is treated at the Everett Water Treatment Facility before distribution. Water hardness measures 60 mg/L — classified as moderately soft.

Everett's moderately soft supply reflects the low-calcium geology of the Sultan River watershed in the Cascade Range. The Sultan River and Spada Lake watershed drains the central Cascade Range — terrain dominated by the Cretaceous Index Batholith (granodiorite and tonalite intrusive complex), Jurassic Hozomeen Group, and overlying Miocene Columbia River Basalt Group flows and Oligocene–Miocene High Cascade volcanic deposits (andesite, dacite, and volcaniclastics). All of these Cascade Range rock types — granitic intrusives and volcanic flows — are mineralogically silica and alumina-dominated, contributing minimal dissolved calcium to watershed drainage. The cool, wet Pacific Northwest climate and large annual precipitation in the Cascade Range ensure high runoff and dilute source water.

With hardness at 60 mg/L, Everett residents experience minimal to moderate scale challenges. Faucet aerators and showerheads develop deposits slowly — bi-monthly cleaning with citric acid solution is sufficient. Dishwashers produce clean glassware with light rinse-aid use. Everett Public Works Water Division consistently delivers water meeting all Washington DOH and EPA Safe Drinking Water Act requirements.