Your appeal deadline is printed on your value notice
Not on a calendar, and — despite what the mailers say — usually not July 1. Here's the actual rule, county by county.
The rule, in one sentence
Your petition to the county Board of Equalization is due the later of July 1 of the assessment year or 30 days after the mailing date printed on your Official Property Value Notice — and your county can extend that 30 to 60 days, which King, Pierce, and Snohomish all have (RCW 84.40.038).
Two things follow from "whichever is later." First, you always get the full window from your own notice, no matter when it mails — a King County notice mailed September 18 is appealable into mid-November. Second, there is no single "Washington deadline" day: your neighbor's window and yours can close weeks apart, because counties mail notices in batches from late spring into fall. The one date that matters is on your notice.
About that "July 1 deadline"
July 1 is a floor, not the deadline. It only controls when it's the later date — mainly for owners whose value didn't change and who therefore never got a notice. For everyone holding a value notice, the clock runs from its mailing date.
Solicitation mailers quote a flat July 1 because urgency sells — and county boards have publicly warned about exactly this. If a letter gives you a deadline that isn't on your own notice, that's your cue about the letter, not your deadline. (California has its own version of this problem — we wrote up how to read a property tax mailer.)
Your county's window
Every Washington county gives at least 30 days from the notice's mailing date. These are the counties where we've verified the extended window on the county's own Board of Equalization page (checked 2026-10-05):
| County | Window after notice mails | Filing fee | Where to confirm |
|---|---|---|---|
| King County | 60 days (or July 1, whichever is later) | Free | Board of Equalization |
| Pierce County | 60 days (or July 1, whichever is later) | Free (per county page) | Board of Equalization |
| Snohomish County | 60 days (or July 1, whichever is later) | Free | Board of Equalization |
| Every other county | At least 30 days — the board's page says whether it's 60 | Free everywhere we've checked | DOR appeals page |
One timing rule worth knowing before you file: since a 2026 law change (SB 6077), the comparable sales you list on your petition can only be swapped later with new evidence submitted at least 21 business days before your hearing — and the assessor must share their evidence with you at least 28 business days ahead. Translation: have your comps right before the deadline, not just a filed form. The full Washington appeal walkthrough is here.
Missed the window? Two honest options
Ask the board anyway. Boards can accept a late petition when you show good cause — the board decides, so file promptly and explain plainly what happened.
Or be ready on day one next year. Washington reassesses every home every year, so a missed window costs one cycle, not your case. Evidence gathered now makes next year's check fast — and we'll happily run the free check again when the new notice lands.
Don't confuse it with the payment deadline
Washington tax bills are due April 30 (first half — or in full when the bill is under $50) and October 31 (second half) under RCW 84.56.020. Keep paying on time even with an appeal pending — late payment accrues interest and penalties, and a successful appeal gets the difference refunded or credited. Appealing never pauses the bill.
No signup. Not everyone qualifies — we'll tell you either way.
Deadline questions, answered straight
Usually not. By law (RCW 84.40.038), your petition is due the LATER of July 1 of the assessment year or 30 days after the mailing date printed on your Official Property Value Notice — and counties can extend that to 60 days, which King, Pierce, and Snohomish all have. Because counties mail notices from late spring into fall, most homeowners' real deadlines fall well after July 1. July 1 only controls when it's the later date — mainly when your value didn't change and no notice was mailed.
Sixty days from the mailing date printed on your value notice, or July 1, whichever is later. King County mails notices in batches from spring into fall, so a notice mailed in September is appealable into November. Read the date off your own notice and count sixty days — don't trust a mailer's date.
Washington assessors mail a notice when your value changes. If your value didn't change, there may be no notice — and July 1 of the assessment year is then the operative deadline under RCW 84.40.038. If you think a notice should have come and didn't, call your assessor's office for the mailing date on record, and confirm your filing window with your county's Board of Equalization.
Not necessarily. County boards can accept a late petition when you show good cause for missing the window — the board decides, so file as soon as you can and explain plainly what happened. And because Washington reassesses every property every year, the worst case is being fully ready the day next year's notice arrives.
No, and mixing them up is expensive. Your tax bill is due April 30 (first half; the full amount if your bill is under $50) and October 31 (second half) under RCW 84.56.020 — keep paying on time even while an appeal is pending, because late payments accrue interest and penalties. The appeal deadline is separate and runs from your value notice. If your appeal lowers the value, the county corrects the bill and refunds or credits the difference.
Because it's the one fixed date in the statute, and it makes a scarier pitch. County boards — Snohomish's publicly among them — warn that solicitation letters quote a false flat July 1 deadline. The letter isn't from your county, and the date on your value notice beats the date on anyone's mailer.