Bonney Lake Water Hardness & Quality Report (2026)

Bonney Lake, Washington, in Pierce County — a Pierce County city in the Puget Sound south metro corridor between Sumner and Enumclaw, a rapidly growing Pierce County community on the Plateau East above the Puyallup River valley — receives its municipal water from Bonney Lake Water Utility or Pierce County Utilities, which draws from the Carbon River or White River (Mount Rainier watershed) through the Pierce County water supply infrastructure.

The very soft 33.5 mg/L hardness and very low TDS of 62.5 mg/L reflect the Carbon River-Mount Rainier watershed's Western Cascades volcanic character. The Carbon River originates in the Mount Rainier National Park (the glaciated Mount Rainier Volcano — Quaternary andesite and basalt — glacial melt and snowmelt) and drains Tertiary basalt and andesite of the Western Cascades. Mount Rainier's glacial melt water is exceptionally pure, and the volcanic rock terrain produces very soft, very low-mineral runoff throughout the Puyallup-Carbon River watershed system.

At 33.5 mg/L, Bonney Lake's water is very soft — excellent for household use. Scale essentially never forms, soap lathers abundantly, and appliances maintain maximum efficiency. Annual descaling is more than sufficient. The PFAS level of 1.9 ppt is excellent — reflecting Mount Rainier's pristine alpine glacial source character and the limited direct military-industrial PFAS sources in the Carbon River upper watershed.