Ellensburg Water Hardness & Quality Report (2026)

Ellensburg, Washington, in Kittitas County — the Kittitas County seat in the upper Yakima River valley, home of Central Washington University, a ranching and agricultural city in the eastern Cascade foothills at Snoqualmie Pass — receives its municipal water from the City of Ellensburg Water Division, drawing from the Yakima River at the Ellensburg water treatment intake in the Kittitas Valley.

The very soft 53 mg/L hardness and TDS of 116.2 mg/L reflect the upper Yakima River watershed's Cascade Range volcanic character. The Yakima River at Ellensburg drains the Cascade Range — Tertiary Cascades volcanic (Columbia River Basalt Group — plateau basalt, largely insoluble), Eocene Roslyn Formation sandstone and coal-bearing strata, and Pleistocene glaciofluvial gravel. The Kittitas Valley floor consists of Quaternary alluvial basalt gravel with limited carbonate content, contributing only minor hardness to the soft Cascade-derived supply.

At 53 mg/L, Ellensburg's water is very soft — essentially no scale forms, soap lathers abundantly, and appliances maintain excellent efficiency. Annual descaling is sufficient. The PFAS level of 2.5 ppt is very good — the upper Yakima watershed above Ellensburg has limited direct PFAS industrial sources, with minor contribution from Ellensburg Airport (AFFF use) and the Kittitas County agricultural corridor.