King County, Washington
Filing deadline: July 1 (earliest possible)
The deadline to appeal is the later of July 1st of the assessment year or 60 days from the mailing date printed on the value notice (or other notice of determination). Late filings are almost always rejected.
What to file
appeal
Approximate effective tax rate
0.84% (published estimate, 2026)
Look up your current assessed value on the county assessor's site →