In Washington, you appeal your home’s assessed value by filing a petition with your county Board of Equalization by July 1 or within the window after your value notice is mailed — 60 days in many counties, whichever is later. Filing is free, you can represent yourself, and you can name someone to file for you. Here’s how it works.
1. Know how your home is valued
Every Washington county assessor must revalue all taxable real property every year, and physically inspect each property at least once every six years. Your home is valued as of January 1 of the assessment year.
In practice, that means the assessor looks at sales from the year before. Pierce County, for example, explains that its January 1, 2026 values are based on 2025 sales.
2. Read your value notice
When your value changes, the assessor mails (or emails) a value notice. Check:
- Assessed value — would your home really have sold for this on January 1?
- Property facts — square footage, bedrooms, bathrooms, lot size, garage, view.
- The mailing date — your appeal deadline is counted from it, so keep the notice.
If something looks wrong, call the assessor’s office first. Some counties, such as Clark, ask you to make a good-faith attempt to resolve issues with the assessor before your hearing. A simple error can often be fixed without a hearing.
3. File your petition by the deadline
You appeal to your county’s Board of Equalization (King County calls it the Board of Appeals and Equalization). State law sets the deadline as the latest of:
- July 1 of the assessment year, or
- 30 days after the value notice was mailed or sent electronically, or
- a longer limit of up to 60 days if the county has adopted one.
Many large counties use 60 days. Check your own county’s board page before you rely on it.
| County | Deadline (whichever is later) |
|---|---|
| King | July 1, or 60 days after the notice’s mailing date |
| Pierce | July 1, or 60 days after the notice is mailed |
| Clark | July 1, or 60 calendar days after the notice’s mailing date |
You must use the petition form approved by the state Department of Revenue. Letters are not accepted, and an incomplete petition may not be considered. File one petition per parcel. Many counties take petitions online (King uses eAppeal; Clark has an online portal), or you can mail it.
Late filing: the board can accept a late petition only for good cause, such as a death or serious illness in the family, a natural disaster, or a documented postal delay. Clark County warns that late appeals cannot be accepted, so don’t count on an exception.
4. Build your evidence
The assessor is presumed correct, so you carry the burden of proof. Pierce County’s instructions say your evidence must be “clear, cogent and convincing.” Your goal is to show the market value on January 1 was lower than the assessed value.
Strong evidence includes:
- Comparable sales — similar homes nearby that sold around January 1 (for a 2026 value, 2025 sales are best)
- An independent appraisal done close to the valuation date
- Contractor bids for repairs a buyer would discount for
- Photos of problems that lower value
- Maps or documents showing easements, traffic, access issues or limits on development
What usually doesn’t work: comparing your assessed value to your neighbors’ assessed values, or averaging. Clark County specifically says not to rely on other properties’ assessed values.
Any evidence you don’t file with the petition must reach the board at least 21 business days before the hearing. The assessor’s response comes to you on the same timeline.
5. Go to your hearing
Hearings are held before a panel of citizen board members. They’re usually short — Clark County schedules about 15 minutes. Depending on the county, you can attend in person or by phone, or ask for a review based on your written materials only.
Hearings can be months away. King County says they’re generally scheduled in the order appeals arrive and may take six months or more.
Bring:
- A one-page summary with the value you’re asking for
- Your comparable sales, with a map
- Photos and repair estimates
The board mails a written decision after the hearing (King County within 45 days; Clark County within 30 days). If your value goes down, the county sends a revised tax statement or a refund.
6. If you disagree: the State Board of Tax Appeals
You or the assessor can appeal the county board’s decision to the Washington State Board of Tax Appeals. The appeal must be filed within 30 days of the mailing date of the county board’s order. Attach a copy of the order. If someone represents you there, you must attach an authorization showing they have full authority to act for you.
7. Using an agent
You don’t have to handle the appeal yourself. You can name a representative on the petition. Pierce County, for example, requires either that you sign the petition’s power of attorney section or that you sign a dated letter of authorization that lists the parcel number, the name of the person or company you’re authorizing, and the year they may petition. King County asks you to list the representative on the petition and include a power of attorney.
Don’t miss the senior and disabled exemption
Separate from an appeal, Washington has a property tax exemption for senior citizens and people with disabilities. You may qualify if, by December 31 of the assessment year, you are 61 or older, unable to work because of a disability, or a qualifying disabled veteran, and your household income is under your county’s threshold. It can exempt you from voter-approved levies, reduce regular levies, and freeze your home’s taxable value. Apply with your county assessor; applications are due by December 31 of the assessment year. Income limits vary by county and are listed by the Department of Revenue.
Or let someone do it for you
You can do all of this yourself for free. If you’d rather not, a property tax consultant can file and argue the appeal for you. Recoup Capital handles Washington appeals for 30% of first-year savings, and you pay nothing if your taxes don’t go down. Get started here, or see where we work. Appealing in another state? Read our Texas protest guide.
Sources: RCW 84.40.038 — Appeals to the board of equalization, RCW 84.41.030 — Annual revaluation, RCW 84.40.020 — Assessment date, King County — Appeal your property tax, King County — How to appeal your valuation, Pierce County — 2026 residential petition instructions, Clark County — Board of Equalization, Board of Tax Appeals — property tax appeal form, Department of Revenue — senior and disabled exemption.