A 2-minute self-check for King County homeowners weighing a 2026 property tax appeal, with five signs your assessed value is worth challenging now.
The 2026 King County filing window runs through July 1, or 60 days from your Official Property Value Notice mail date, whichever is later. Across King County, appeal signals change by market: Seattle arterial-edge homes, Bellevue teardown-adjacent lots, Renton airport-noise parcels, and Kent Valley industrial adjacency all need different evidence.
What to do next
If the self-check raised a question, you can look it over yourself, or use FairAppeal to see if you are overpaying. In King County, the question is whether the assessed value still fits the home a buyer would actually see. Fair Appeal handles the full King County appeal from review through hearing and only charges a percentage of first-year tax savings when the appeal wins.
For the broader context, see our King County property tax appeal guide, or the city-specific guides for Seattle, Bellevue, Kirkland, Redmond, and Renton.
Look up if you are overpaying on your King County home.
King County reassesses every home every year and leans on neighborhood comps without seeing condition.