California Property Tax Appeal Deadline 2026: September 15 or November 30?

Which counties close September 15, 2026

Per the State Board of Equalization's official filing period notice for 2026 (Letter To Assessors 2026/023), eleven counties require your Assessment Appeal Application by September 15: Alameda, Alpine, Inyo, Kings, Mono, Placer, San Francisco, San Luis Obispo, Santa Clara, Sierra, and Ventura.

If your property is in any other California county, including Los Angeles, San Diego, Orange, Riverside, San Bernardino, and Sacramento, your deadline is November 30, 2026.

The difference comes down to a technicality: counties where the assessor mails value notices to every owner on the secured roll by August 1 get the earlier deadline. Everyone else gets the extended window.

What you file, and where

The form is the Assessment Appeal Application, BOE-305-AH. You file it with the Clerk of the Board (or the Assessment Appeals Board directly) in the county where the property sits, not with the assessor.

Filing the form is free or nearly free in most counties, though some charge a small processing fee. You do not need a lawyer or a tax agent. Homeowners represent themselves at appeals board hearings every day.

Before filing, pull your current assessed value from your county assessor's website and compare it against what similar homes in your neighborhood are assessed at per square foot. That gap is your case.

Why 2026 is a strong year to appeal in California

Assessed values under Proposition 13 rise automatically by up to 2 percent per year, but market conditions in parts of the state have softened since the 2022 peak. When your market value falls below your factored base year value, you are entitled to a temporary reduction under Proposition 8, and the appeals board is the mechanism to force one if the assessor does not grant it voluntarily.

Condo owners, recent buyers who purchased near the market top, and owners in areas with flat or falling prices are the strongest candidates. If homes like yours now sell for less than your assessed value, you have a live Prop 8 claim for the 2026-27 tax year.

The evidence that wins: comparable properties

Appeals boards respond to one thing above all else: comparable sales and comparable assessments. Three to five similar properties, same neighborhood, similar size and age, either sold for less than your assessed value or assessed lower per square foot than yours.

Your county assessor's public records portal lists assessed values for every parcel. Pull comps, compute per square foot values, and put them in a table. A one page letter with a clean comps table beats ten pages of argument.

Do not wait for the hearing to organize this. Many counties resolve appeals informally with an assessor stipulation before the hearing date, and that only happens when your filing already contains convincing evidence.

What happens after you file

The clerk schedules your hearing, which in busy counties can be many months out. That is normal, and your place in line is protected as long as you filed inside the window.

Important: keep paying your property tax bill while the appeal is pending. If you win, the county refunds the difference with interest. If you skip payment, you rack up penalties that an appeal victory does not erase.

Hearings themselves are short, usually 10 to 15 minutes. You present your comps, the assessor's staff presents theirs, and the board decides. Boards reduce assessments in a substantial share of residential cases where the owner shows up with real evidence.