Washington vs. California Property Tax Appeals: Key Differences
By Danielle Cui · June 18, 2026
If you own property in both California and Washington — or you're moving between them — don't assume the property tax appeal playbook is the same. The valuation systems are fundamentally different.
How value is set
- California: Proposition 13 sets a base-year value (usually your purchase price) that can rise at most 2% per year. Your assessment is often below market — until the market drops below it, which is when a Proposition 8 appeal for a temporary reduction makes sense.
- Washington: counties reassess to 100% of market value every year. No base-year value, no 2% cap. Your assessment is meant to track the market annually, so an appeal simply argues the Assessor's market value is too high.
Where you appeal
- California: the county Assessment Appeals Board (e.g., San Francisco, Alameda, Santa Clara).
- Washington: the county Board of Equalization (e.g., King County).
The deadlines
- California: the regular filing period is July 2 to September 15 (confirm by county). Sales more than 90 days after the January 1 lien date can't be used as comps (RTC §402.5).
- Washington: file by July 1, or within 60 days of your value-change notice, whichever is later. Valuation date is January 1.
What stays the same
In both states, the heart of your case is comparable sales — recent, arms-length sales of similar homes near the January 1 valuation date, matched on location, type, size, age, condition, and features. The board respects clean, well-organized comps. (How to choose them.) CompFinder handles the comp research and analysis in both states.
The takeaway: same evidence, different rules and deadlines. Use the California guide for CA properties and the King County guide for WA.
Frequently asked questions
Does Washington have Proposition 13?
No. Washington reassesses property to 100% of market value annually, with no base-year value or 2% cap. Proposition 13 is California-only.
Are property tax appeal deadlines the same in WA and CA?
No. California's regular period is July 2–September 15. Washington's is July 1 or within 60 days of your value-change notice, whichever is later.
Is the evidence for an appeal the same in both states?
Largely, yes — both rely on recent arms-length comparable sales near the January 1 valuation date, matched on the key property characteristics. The rules and boards differ, not the core evidence.