Many people repeat that "the deadline is July 1" for property tax appeals in Washington, but that’s not true for much of King County. The actual rule is July 1, or 60 days after the mailing date printed on your value notice, whichever is later. King County sends out notices in different areas from June through the fall, not all at once.

This year, the last notices were mailed in September. If you received one then, you still have time to appeal, but your deadline is in November.

King County's September 2026 value notice batches and their appeal deadlines: mailed September 3, deadline November 2; September 10, November 9; September 17, November 16; September 24, November 23.
King County's 2026 residential notice mailing dates, plus 60 days. Source: King County Assessor, 2026 residential notice mailing dates.

Which areas, which date

  • Mailed September 3, appeal by November 2: Normandy Park, Maple Valley, Black Diamond / East Maple Valley, Lake Youngs, Duvall, Baring / Skykomish, and Carnation / Fall City / Snoqualmie.
  • Mailed September 10, appeal by November 9: Bothell; Roosevelt, Wedgwood and Bryant in Seattle; Burien.
  • Mailed September 17, appeal by November 16: Bridle Trails, Wilburton and Central Bellevue; Sherwood, Bel-Red and SW Redmond; East Kirkland / Rose Hill.
  • Mailed September 24, appeal by November 23: Auburn and West Hill Auburn, Kentridge, Kent Meridian / East Hill, Lea Hill / Lake Meridian, Federal Way, Twin Lakes, Jovita, Woodmont / Redondo, Steel Lake / Star Lake, and Des Moines / SeaTac / West Kent.

If your notice was mailed in August, your deadline was in mid-October and has now passed. The important date is the one printed on your own notice. If it’s different from the list above, always go by what your notice says.

Remember, the deadline is not based on when you opened the envelope. It’s 60 days from the date printed on your notice.

What to do this week

  1. Look for the mailing date on your notice and add 60 days. Mark that exact date on your calendar instead of just writing down "sometime in November."
  2. Check how your home’s value compares to recent sales of similar homes. Your notice lists the county’s value as of January 1, 2026. What matters most are sales of homes like yours around that date. You can look this up using the Assessor’s sales search or use the free check on this site.
  3. Submit your appeal before the deadline. Filing online with King County eAppeals is free and the quickest option. If you mail your petition, make sure it’s postmarked by the deadline. You’ll need your parcel number, the Assessor’s value, and your own estimate of value with reasons to support it.

Filing an appeal doesn’t mean you have to go to a hearing. After you file, the Assessor will review your petition and often responds with a recommendation before any hearing is scheduled (that’s how mine ended). But if you miss the deadline, none of this can happen.

The full walkthrough is in the step-by-step guide.