Photo: Redideo / Wikimedia Commons (CC BY 4.0)
Every property tax bill in San Diego County starts with one number: the assessed value set by the County Assessor. If you believe that value is higher than what your property was actually worth on Jan. 1, California law gives you two routes to challenge it. Neither one requires paying a consultant.
How assessed value works under Proposition 13
Under Proposition 13, a property’s base value is generally set when it is bought or newly built, and the assessed value can rise by no more than 2% a year after that. Proposition 8, approved by voters in 1978, allows a temporary reduction when market value falls below that assessed value on the Jan. 1 lien date. Once reduced, the value is reviewed each year and can move back up, but never above the original base value plus the annual 2% increases.
Option 1: A free informal review with the Assessor
The Assessor’s Office accepts “Review of Assessment” (Proposition 8) requests from Dec. 1 through April 30. You submit the form online or at an Assessor/Recorder/County Clerk branch office, and an appraiser reviews your property against recent sales. There is no fee. Private companies often mail letters offering to file this request for a charge; the county notes that owners can file it themselves for free.
Option 2: A formal appeal to the Assessment Appeals Board
If you disagree with the value on your annual notice, you can file an application with the Clerk of the Board of Supervisors. In San Diego County, the regular filing period for annual assessments runs July 2 through Nov. 30, and applications can be filed online through the county’s assessment appeal portal. Mailed applications count as filed on the USPS postmark date.
Other assessments have their own deadlines: supplemental and escape assessments must generally be appealed within 60 days of the notice date, and calamity reassessments within 180 days.
Building your case
- Comparable sales. Recent sales of similar homes near yours, as close to Jan. 1 as possible, are the strongest evidence.
- Condition. Photos and repair estimates for problems a buyer would discount.
- Errors. Check the Assessor’s record for square footage, lot size and room counts.
Hearings are held before an Assessment Appeals Board or a hearing officer. Bring copies of your evidence and be ready to explain why your opinion of value is right.
Sources
- County of San Diego Clerk of the Board: assessment appeal filing dates
- San Diego County Assessor: real property assessment
- California State Board of Equalization: 2026 appeals filing periods
By 
