Bothell Water Hardness & Quality Report (2026)

Bothell, Washington, in King and Snohomish Counties north of Seattle — a major North Seattle suburban community on the North Creek and Sammamish River corridor, home of UW Bothell (University of Washington Bothell campus), one of the fastest-growing cities in the Seattle metro area, a significant tech industry suburban community with major corporate presences (including the Canyon Park business district), and a gateway community to the Cascade foothills — draws its municipal water supply from the Cedar River Watershed or Northshore Utility District supply. Water hardness in Bothell measures 35 mg/L — classified as very soft.

Bothell's very soft supply reflects the Seattle metro Cascade Range watershed's calcium-poor volcanic and glacial geology. The Cedar River watershed (draining the Cascade Range — Quaternary volcanic basalt and andesite from the Cascade volcanic arc and Tertiary calcareous-poor sandstone and volcanic sediment — highly calcareous-poor source water); Pleistocene glacial till and outwash of the Puget Sound lowlands (calcareous-poor glacial deposits from the Puget Lobe of the Cordilleran Ice Sheet). The calcium-poor Cascade volcanic and crystalline watershed and Puget Sound glacial outwash produce the very soft 35 mg/L at Bothell.

With hardness at 35 mg/L, Bothell residents enjoy very soft water with virtually no scale challenges. Northshore Utility District consistently delivers water meeting all Washington State DOE and EPA Safe Drinking Water Act requirements.