Washington assesses at 100% of market value — and when your Official Property Value Notice arrives, you typically have 30 days (60 in King County and others) to petition your county Board of Equalization. Filing is free, homeowner-friendly, and decided on evidence. Ours helps you build it.
Your county mails an Official Property Value Notice when your value changes (King County: summer, in valuation-cycle waves). The petition deadline is printed on it — usually 30 or 60 days from mailing, or July 1, whichever is later.
County assessor portals are excellent here — King County's eReal Property shows every sale and characteristic. Build your case in the worksheet below.
Form 64 0075 to your county Board of Equalization — free, online in most counties. State the value you believe is correct and attach your comps.
Informal BOE hearing (many by phone). Disagree? Appeal to the State Board of Tax Appeals within 30 days — still no lawyer required.
RCW 84.40.0301 puts the burden on you: bring "clear, cogent and convincing" evidence — comparable sales near the January 1 assessment date, condition photos, or an appraisal. A petition with no evidence attached is how appeals get denied. Use the worksheet.
Everything runs in your browser — we never see or store your property data.
Washington levies are budget-based, so your exact savings depend on district rates (typically 0.8–1.1% of value; King County averages near 1%). The 0.87% default approximates the statewide average effective rate. Estimates only; not tax advice.
Enter sales of similar homes near the January 1 assessment date (King County: eReal Property; other counties: assessor parcel search). The worksheet computes price per square foot and a suggested value.
| Address | Sale Date | Sale Price ($) | Sq Ft | $/Sq Ft |
|---|
| Item | Washington Rule |
|---|---|
| Petition deadline | July 1 of the assessment year OR 30 days from the notice mailing date, whichever is later — counties may extend to 60 days by ordinance (King County: 60) |
| Form | Taxpayer Petition, DOR Form 64 0075 — filed with your county Board of Equalization (free) |
| Value standard | 100% of true and fair market value as of January 1 (RCW 84.40.030) |
| Burden of proof | On the taxpayer — clear, cogent and convincing evidence (RCW 84.40.0301) |
| Hearing | Informal; phone/video common; no attorney required |
| Next level | State Board of Tax Appeals within 30 days of the BOE decision |
| Records | King County eReal Property + assessor data downloads; other counties' parcel search portals |