Appeal to your county Board of Equalization by July 1 of the assessment year or within 60 days of the mailing date on your value notice, whichever is later. The assessor is presumed correct, so bring market evidence dated near January 1. If an appraisal would help your case, request a quote with the form below or call (425) 967-3498.
Checked October 9, 2026 against the statutes, state pages and county pages listed under Sources. Your own deadline is printed on your notice.
What date does the assessor value?
January 1 of the assessment year. Washington assesses property "with reference to its value on the first day of January of the year in which it is assessed" (RCW 84.40.020). A notice mailed in summer 2026 reports the value as of January 1, 2026, so the hearing asks what the home was worth then. Pierce County's 2026 instructions put it plainly: sales from 2025 close to January 1, 2026 are the most relevant, and older sales count for less (Pierce County, Completing Your Appeal Petition).
Who hears the appeal?
Your county Board of Equalization, which is separate from the assessor's office. If you lose there, you can appeal to the Washington State Board of Tax Appeals within 30 days after the county board mails its decision (RCW 84.08.130).
When is the deadline?
The latest of July 1, 30 days after the notice was mailed or sent electronically, or a longer window of up to 60 days if the county adopted one (RCW 84.40.038). King, Pierce and Snohomish each publish a 60 day window, counted from the date on the notice.
A board may waive a missed deadline only for good cause: death or serious illness of the taxpayer or immediate family, being away from home more than 15 days before a deadline that falls after July 1, wrong written advice from board, assessor or tax advisor staff, a natural disaster, a documented postal delay, or no notice received for an unchanged value in a revalued area. Do not plan on one.
What evidence wins?
Market evidence for January 1. The Department of Revenue's taxpayer guide says "the assessor, by law, is presumed to be correct" and that "you must present clear and convincing evidence to support your estimate of market value" (DOR, Appealing Your Property Assessment). It suggests:
- sales of similar homes at lower prices, with a map showing them against your home
- an appraisal
- written repair estimates and third party documents describing problems
- photographs of condition
The same guide warns that comparing assessments or percentage increases is not enough. Snohomish County adds that you must show both that the assessor erred and what the market value was on the assessment date.
Do you need an appraisal?
No. Snohomish County's appeal guide says a professional appraisal "is not a requirement to have a successful appeal," and plenty of simple cases win on well chosen sales and photos. An appraisal earns its cost when the home has condition problems a mass model cannot see, the lot or house is unusual, nearby sales do not fit the model, or the dollars at stake are large.
A tax appeal appraisal from AppraisalMS is dated to January 1 of the assessment year, uses sales from around that date, documents condition, and explains each adjustment for readers who may not be appraisers. Gerry Allard has testified as an expert witness in multiple landmark legal cases, and a board hearing rewards the same habit: every number gets a plain reason. The fee depends on the property and scope and is quoted up front, and delivery is typically 7 to 10 days, so order well before your evidence cutoff.
King County
| Item | Detail |
|---|---|
| Board | King County Board of Equalization, 516 Third Avenue, Room 1222, Seattle, WA 98104. Petitions are not accepted by email. |
| Deadline | Postmarked, hand delivered or filed online by July 1 of the assessment year or within 60 days of the mailing date on the value notice, whichever is later. The board's page has a parcel lookup for your exact due date. |
| Before filing | The assessor asks owners who see an error to call 206-296-7300 first. |
| How to file | Online through eAppeal, or by mail or hand delivery. Paper filings go in duplicate. |
| Evidence | Comparable sales, easements or development limits, environmentally sensitive areas, professional repair estimates. Due 21 business days before the hearing, from both sides. |
| Free help | The King County Property Tax Advisor, for residential appeals: 206-477-1060 or taxadvisor@kingcounty.gov. |
| Filing fee | None mentioned on the county's pages. Confirm with the board. |
Official pages: Board of Equalization · Assessor: how to appeal your valuation · eAppeals
Pierce County
| Item | Detail |
|---|---|
| Board | Pierce County Board of Equalization, 2401 South 35th Street, Room 176, Tacoma, WA 98409. Phone (253) 798-7415. |
| Deadline | Within 60 days of the mailing date on the value change notice, or by July 1 of the assessment year, whichever is later. The exact date is printed on the front of the notice. |
| Notices | Mailed in late June or early July after the rolls close, with a second mailing in late September or October for new construction. |
| How to file | Paper petition, single sided and signed, by mail or hand delivery. Email is not accepted, and the county's pages describe no online filing. |
| Evidence | Sales from the correct year, contractor bids for defects, independent appraisals, photos. Evidence not filed with the petition is due 21 business days before the hearing. The standard is clear, cogent and convincing evidence, and the board will not research your case for you. |
| Filing fee | None mentioned on the county's pages. Confirm with the board. |
Official pages: Board of Equalization · Residential property appeals · 2026 appeal tutorial (PDF)
Snohomish County
| Item | Detail |
|---|---|
| Board | Snohomish County Board of Equalization, Admin West Building, 1st Floor, 3000 Rockefeller Avenue, M/S 409, Everett, WA 98201. Phone 425-388-3407. Email boe@snoco.org, though petitions and evidence are not accepted by email. |
| Deadline | Received by July 1 of the assessment year or within 60 calendar days after the date of the value notice, whichever is later. Mailed petitions must be postmarked by the deadline; electronic filings are due by 4:00 PM. |
| 2026 notices | Mailed June 26, 2026. The board's page says that appeal deadline has passed; ask the clerk if you think a late filing exception applies. |
| How to file | Electronically through the county website as a single PDF or Word document, or on paper by mail or in person. |
| Evidence | Comparable sales on the county's worksheet, repair bids, photographs. A maximum of 75 pages, due 21 business days before the hearing to both the board and the assessor. |
| Filing fee | None. The county's FAQ says "There is no charge for filing an appeal." |
Official pages: Board of Equalization · Appeal process guide · Petition form · FAQ
What about Kitsap and Thurston Counties?
The same state law applies, including the January 1 valuation date and the July 1 or 30 to 60 day deadline. This guide does not cover those counties' local rules, so call the Kitsap County or Thurston County Board of Equalization for their window and filing steps.
What if you lose at the county board?
Appeal to the Washington State Board of Tax Appeals within 30 days of the mailing date of the county decision. The state board says it cannot extend that deadline or accept late appeals, and a deadline that lands on a weekend or holiday moves to the next business day. File a notice of appeal with a copy of the county board's order by email to bta@bta.wa.gov, by mail to PO Box 40915, Olympia, WA 98504-0915, by delivery to 1110 Capitol Way South, Suite 307, Olympia, or by fax to 360-586-9020. The state board also presumes the assessed value is correct and asks for clear, cogent and convincing evidence. Details: How to file · FAQ · Filing deadlines and calculator.
Should you check exemptions too?
Yes, if you are a senior, retired due to disability, a veteran with a disability, or a homeowner with limited income. An appeal changes the value; an exemption or deferral changes the bill. You apply through your county assessor, and each county sets its own income limits. See the Department of Revenue's exemption program, deferral programs and income thresholds.
What is the order of steps?
- Write down your deadline from the mailing date on your notice.
- Pull three to five closed sales of similar homes from the months around January 1 of the assessment year.
- If they support a lower value, file the petition before the deadline. Evidence can follow, up to the board's cutoff.
- If the case is complicated or the dollars are large, order an appraisal dated to January 1, early enough to meet that cutoff.
- Attend the hearing and stick to the evidence.
Not sure your assessment is worth fighting? Ask Gerry, free and without obligation.
Sources
- RCW 84.40.020, valuation as of January 1
- RCW 84.40.038, petition deadlines and waivers
- RCW 84.08.130, appeal to the Board of Tax Appeals
- WA Department of Revenue, Appealing Your Property Assessment to the County Board of Equalization
- King County Board of Equalization, appeal your property tax
- King County Assessor, how to appeal your valuation
- King County Assessor, residential FAQ
- Pierce County Board of Equalization
- Pierce County, residential property appeals
- Pierce County, completing your appeal petition
- Pierce County, Appealing Your Assessed Value 2026 tutorial
- Snohomish County Board of Equalization
- Snohomish County, appeal process guide
- Snohomish County, Board of Equalization FAQ
- Snohomish County, rules of practice and procedure
- Snohomish County, 2026 value notices news release (June 25, 2026)
- Washington State Board of Tax Appeals, how to file
- Washington State Board of Tax Appeals, FAQ
- Washington State Board of Tax Appeals, filing deadlines