Browse source-reviewed property tax appeal guides for Washington. County deadlines, filing methods, and available records can differ by county and tax year.
Each published guide identifies the public sources used for its deadline and filing summary. Confirm current requirements with the official filing authority before submitting anything.
King County: 2026 deadline guidance is Later of July 1, 2026 or 60 days after the value-notice mailing date. Guide: https://fairpath.app/property-tax-appeal/washington/king-county
Pierce County: 2026 deadline guidance is Later of July 1, 2026 or 60 days after notice mailing. Guide: https://fairpath.app/property-tax-appeal/washington/pierce-county
Snohomish County: 2026 deadline guidance is August 25, 2026 at 4:00 p.m.. Guide: https://fairpath.app/property-tax-appeal/washington/snohomish-county
Source: King County Assessor, 2026 Property Taxes and Calendar, https://kingcounty.gov/en/dept/assessor/buildings-and-property/property-taxes/property-tax-overview/2026-taxes. Reviewed 2026-07-16.
Source: King County Assessor, File Your Appeal Online, https://kingcounty.gov/en/dept/assessor/buildings-and-property/property-value-and-information/appealing-a-valuation/file-appeal-online. Reviewed 2026-07-16.
Source: King County Assessor, How to Appeal Your Valuation, https://kingcounty.gov/en/dept/assessor/buildings-and-property/property-value-and-information/appealing-a-valuation/how-to-appeal-your-valuation. Reviewed 2026-07-16.
Source: King County Board of Appeals and Equalization, How to Appeal a Property Tax Assessment, https://kingcounty.gov/en/independents/governance-and-leadership/government-oversight/board-appeals-equalization/appeal-property-tax. Reviewed 2026-07-16.
Source: Pierce County, Board of Equalization, https://www.piercecountywa.gov/5920/Board-of-Equalization. Reviewed 2026-07-16.
Source: Pierce County Assessor-Treasurer, Residential Property Appeals, https://www.piercecountywa.gov/9045/Residential-Property-Appeals. Reviewed 2026-07-16.
Source: Snohomish County, Board of Equalization, https://www.snohomishcountywa.gov/134/Board-of-Equalization. Reviewed 2026-07-16.
Source: Snohomish County, Board of Equalization FAQ, https://snohomishcountywa.gov/m/faq?cat=60. Reviewed 2026-07-16.
Source: Snohomish County Assessor, Tax Statement Versus Assessed Value Notice, https://www.snohomishcountywa.gov/380/Tax-Statement-Vs-Assessed-Value-Notice. Reviewed 2026-07-16.
Source: Washington Department of Revenue, Appealing Your Property Assessment, https://dor.wa.gov/sites/default/files/2022-02/AppealPropAssess.pdf. Reviewed 2026-07-16.