California note
A temporary Prop 8 assessment reduction can rise again
A Prop 8 decline-in-value assessment is reviewed each year and can rise with the market, while a formal assessment appeal has a county filing deadline.
Start with the county assessor. Check whether the property’s market value on January 1 is less than its factored base-year value. January 1 is the lien date for the annual assessment.
A Prop 8 decline-in-value cut changes the assessment for that year. It does not promise the same cut on later bills. The assessor reviews the Prop 8 value each year. As the market comes back, the assessed value can rise by more than 2 percent in one year. But it cannot go above the factored base-year value unless another event applies, such as a change in ownership or new construction.
Ask for the county’s informal review early. Do not let that talk run past the formal appeal deadline. For a regular annual assessment, the filing period is July 2 through September 15. It runs through November 30 in counties where the assessor does not mail all value notices by August 1. Check the last day with the county clerk of the assessment appeals board. Supplemental, escape, and some notice-based assessments have different filing windows.
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Reviewed July 14, 2026
Current rules, forms, fees, deadlines, maps, and office instructions.
Rules, forms, fees, deadlines, and office procedures can change. Check the current page before you file, pay, or rely on a date.
Related notes
Related California notes
A change in ownership can reassess only the interest that changed
A California assessor generally reappraises the ownership interest that changed, unless a statutory exclusion applies and any required claim is filed.
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