When is the King County property tax appeal deadline in 2026?

The 2026 King County filing window runs through July 1, or 60 days from your Official Property Value Notice mail date, whichever is later. Most notices mail between May and November, so the 60-day rule is what most homeowners actually face.

Who hears a King County property tax appeal?

The King County Board of Equalization hears the appeal. It is a separate body from the King County Assessor, which sets the value on the notice. The Board is the forum that can change the assessed value for the year under appeal.

How much does a King County property tax appeal cost?

A FairAppeal review has no upfront cost. If an appeal is filed and the tax goes down, the fee is a percentage of first-year tax savings. If FairAppeal does not file, or the appeal does not succeed, you owe nothing.

What if I missed the King County property tax appeal deadline?

Missing both the July 1 date and the 60-day notice window usually means the 2026 assessed value stands for the year. Late relief is rare. The next Official Property Value Notice opens a new window, and a free review can still flag the home for that cycle.

Should I appeal my King County property tax if the notice just looks high?

A high-feeling 2026 notice is a real signal, not a reason to shrug it off. King County taxes the assessed value, so an inflated number shows up on the next bill and again the year after until the value is challenged. A free review is the low-friction way to find out.

Should I Appeal My King County Property Tax in 2026? | FairAppeal

In short

Yes, a 2026 King County property tax appeal is worth reviewing when the assessed value looks higher than the home a buyer would actually pay for. The 2026 King County filing window runs through July 1, or 60 days from your Official Property Value Notice mail date, whichever is later, per the King County Board of Equalization.

King County

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.

Local facts

Place: King County
Board: King County Board of Equalization
Window: July 1, or 60 days from your Official Property Value Notice mail date, whichever is later

Should I appeal my King County property tax this year?

King County reassesses every home every year, from Capitol Hill walk-ups to Kent Valley lots, so a 2026 notice can jump even when the house has not changed. That number drives the tax bill paid the following year. If the assessed value feels ahead of what the home would actually trade for, the overage repeats until someone takes the case to the King County Board of Equalization.

FairAppeal handles the entire appeal on your behalf and only charges a percentage of first-year tax savings when the appeal wins. A Fair Appeal review costs nothing to start. For the broader context, see our King County property tax appeal guide, or the city-specific guides for Seattle, Bellevue, Kirkland, Redmond, and Renton.