Inglewood-Finn Hill Water Hardness & Quality Report (2026)

Inglewood-Finn Hill, Washington, in King County on the Sammamish Plateau east of Lake Washington near Kirkland — a primarily residential Sammamish Plateau community adjacent to Juanita and Kingsgate — receives its municipal water from the Northshore Utility District or through the Seattle Public Utilities (SPU) regional water supply network, which draws from the Cedar River Watershed and Tolt River Watershed in the Cascade Mountains east of Seattle. The Northshore Utility District serves the northeast King County plateau communities through a network connected to SPU's regional water system.

The very soft 43 mg/L hardness and low TDS of 87.2 mg/L reflect the Pacific Northwest Cascade Mountain watershed's characteristic soft water geology. The Cedar River and Tolt River drain the Western Cascade Range — a terrain of Eocene Roslyn Formation volcanic rocks, Oligocene and Miocene volcanic intrusions, and the Snoqualmie Batholith (granodiorite pluton) — all igneous and metamorphic rock terrains with essentially no soluble carbonate content. Pacific Northwest precipitation falling on these Cascade volcanic terrains picks up minimal dissolved minerals, producing the characteristically soft, clear water throughout the King County plateau supply zone.

At 43 mg/L, Inglewood-Finn Hill's water is very soft — excellent for household appliances and comfortable for everyday use. Scale forms very slowly over many months in kettles and appliances, soap lathers generously, and the dishwasher produces spotless results. Semi-annual to annual descaling of heating appliances is adequate. The PFAS level of 2.2 ppt is excellent — the Sammamish Plateau's predominantly residential character, distance from heavy industrial and military PFAS sources, and the well-protected Cascade Mountain watershed supply result in one of King County's better PFAS readings for this plateau community.