How to appeal your property tax value in California

4 sourced points for California, each linked to the official page it comes from.

File an assessment appeal application with the clerk of the board of supervisors, which sits as the local board of equalization or assessment appeals board. The filing period starts July 2 and ends September 15 or November 30, depending on the county. boe.ca.govOct 21
Supplemental and escape assessments must be appealed within 60 days after the notice of change in assessment is mailed. boe.ca.govOct 21
Usually you have to prove the assessor valued the property wrong. For an owner-occupied single-family home that's your principal residence, the assessor has to prove the value is right. boe.ca.govOct 21
If the county board denies your appeal, you can go to superior court only in certain cases. The court won't take new evidence of value and only reviews the record. boe.ca.govOct 21

The dates

Date and source	Deadline	Applies to
Varies, see rule set by noticeboe.ca.govOct 21	Appeal deadline Regular appeal window July 2 to September 15 in counties where the assessor mails value notices to all owners by August 1. July 2 to November 30 everywhere else. File with the county assessment appeals board. Each county's 2026 date is listed below.	All 58 California counties