Key Facts: King County Tax Appeals
| County | King County |
| State | Washington (WA) |
| Required Form | REV 64 0075 |
| 2026 Deadline | July 1, 2026 |
| Mailing Address | 516 Third Avenue, Room 1222, Seattle, WA 98104 |
| Millage Rate | 0.01 mills |
| Official Website | King County Assessor → |
Generate Your Appeal Form
Use our automated tool to generate a pre-filled REV 64 0075 for King County. All data is processed locally in your browser — we never see or store your personal information.
Automated Mapping in Progress
We haven't automated this specific county's fields yet, but you can download the official blank form and follow the mailing instructions.
Estimate Your Tax Savings
Use our calculator below to estimate how much you could save on your annual property taxes by successfully challenging your King County assessment. The calculation uses the local millage rate of 0.01 mills.
Tax Savings Calculator
Potential Annual ROI
Based on estimated King millage rates.
*Disclaimer: Calculations are estimates for informational purposes. Actual savings depend on assessment methods and local exemptions.
How the Property Tax Appeal Process Works in Washington
Property tax appeals in Washington follow a structured administrative process. As a property owner in King County, you have the legal right to challenge your property's assessed value if you believe it does not accurately reflect the fair market value. Understanding the process is the first step toward potentially lowering your tax bill.
Step 1: Review Your Assessment Notice
Each year, the King County Board of Tax Assessors sends property owners an assessment notice that includes the assessed value of their property. Review this notice carefully and compare the assessed value to what you believe your property would realistically sell for on the open market. If the assessed value seems too high, you may have grounds for an appeal.
Step 2: Gather Supporting Evidence
Building a strong case is critical to a successful appeal. The most effective evidence includes:
- Comparable sales (comps): Recent sales of similar properties in your neighborhood that sold for less than your assessed value. Focus on properties with similar size, age, condition, and location.
- Independent appraisal: A professional appraisal from a licensed appraiser that establishes a lower fair market value.
- Property condition issues: Documentation of structural defects, foundation problems, environmental hazards, or other conditions that reduce market value.
- Assessment errors: Incorrect square footage, lot size, room count, or other factual errors in the property record card.
- Photos and documentation: Before-and-after photos, repair estimates, and any other visual or written evidence supporting your claim.
Step 3: File Your Appeal
Complete the official REV 64 0075 and submit it to the King County Board of Tax Assessors before the deadline of July 1, 2026. Mail your completed form to: 516 Third Avenue, Room 1222, Seattle, WA 98104. Most counties also accept appeals in person at the assessor's office. Some states now allow electronic filing — check with your county for the most current options.
Step 4: Attend Your Hearing
After filing your appeal, you will typically be scheduled for a hearing before the Board of Equalization or a similar administrative body. At the hearing, present your evidence clearly and concisely. Focus on the data — comparable sales and factual errors are the most compelling arguments. You do not need an attorney to represent you at a property tax appeal hearing, although you may choose to hire one.
Step 5: Receive the Decision
The board will review your evidence and either reduce your assessed value, maintain the original assessment, or in rare cases, increase it. If you are not satisfied with the decision, you typically have the right to appeal further to a superior court or state-level tax tribunal, depending on your state's specific process.
Frequently Asked Questions: King County Property Tax Appeals
How do I appeal my property taxes in King County?
Complete the REV 64 0075 and mail it to the King County Board of Tax Assessors at 516 Third Avenue, Room 1222, Seattle, WA 98104. You can generate a pre-filled form using our free tool above.
What is the deadline to file a property tax appeal in King County?
The 2026 property tax appeal deadline for King County is July 1, 2026. Appeals must typically be received (not just postmarked) by 5:00 PM on this date.
What evidence do I need for a property tax appeal?
The strongest evidence includes recent comparable sales showing similar properties sold for less than your assessed value, an independent appraisal from a licensed appraiser, documentation of property defects or damage, and proof of any errors in the assessment (such as incorrect square footage or lot size). Presenting 3-5 comparable sales within a 1-mile radius from the past 12 months is typically the most effective approach.
Does filing a property tax appeal cost money?
In most jurisdictions, filing a property tax appeal is free. There is no filing fee for the initial appeal to the Board of Equalization. However, if you choose to hire a professional appraiser or attorney to assist you, those costs are your responsibility. Our form generation tool is completely free to use.
Can my property taxes increase as a result of an appeal?
Yes, in some jurisdictions the Board of Equalization has the authority to increase your assessed value if they determine your property is actually undervalued. However, this is relatively rare. Most appeals result in either a reduction or no change. It is important to research comparable sales thoroughly before filing to ensure your appeal is well-supported.