Grandview Water Hardness & Quality Report (2026)

Grandview, Washington, in Yakima County — a Yakima County city adjacent to Sunnyside and Mabton in the lower Yakima Valley of south-central Washington — receives its water from the City of Grandview Water Department, drawing from the Yakima River through the south-central Washington distribution.

The very soft 47 mg/L hardness and low TDS of 97.5 mg/L reflect the Yakima County Yakima River supply's very soft Cascade volcanic character — the Miocene Columbia River Basalt and Quaternary Cascade andesite are highly insoluble volcanic formations contributing minimal dissolved minerals to the pristine Yakima watershed (compare Sunnyside WA: 45/93 in Yakima County comparable; Mabton WA: 48/101 in Yakima County comparable; Grandview consistent very soft from the same Yakima County Yakima River Miocene basaltic supply). The Yakima watershed — Miocene Columbia River Basalt (insoluble — primary dilutant), Quaternary Cascade andesite (insoluble — secondary dilutant), and Quaternary Yakima Valley alluvium (slightly calcareous — minimal TDS).

At 47 mg/L with TDS 98, Grandview's water is very soft — minimal scale buildup. Soft water can be mildly corrosive — check for blue-green copper staining in older plumbing. The PFAS level of 2.3 ppt is very low — a clean result for south-central Washington. Review the City of Grandview's annual water quality report.