State Guide

How to Appeal Your Property Taxes in California (2026 Guide)

Published July 10, 2026

If you own a home in California, your county assessor mails an assessment notice showing what the county thinks your property is worth. That number becomes the basis for your tax bill — and every year you have a statutory window to challenge it before it's locked in.

The California deadline: September 15 or November 30

California's appeal window opens July 2. When it closes depends on your county, under Cal. Rev. & Tax. Code §1603: November 30 in most counties, and September 15 in the minority whose assessor mails every owner an annual value notice by August 1. You file an Application for Changed Assessment with your county assessment appeals board — not a state agency, not the assessor's office directly.

As of the 2025 filing periods, 47 of California's 58 counties used the November 30 date and only 11 used September 15. Because each county sets its choice annually, always confirm the exact date with your clerk of the board — and if you file by September 15, you're on time in every county.

How California assesses your home

California is a Prop 13 state, so it does not tax your home at this year's market value. Under Proposition 13 (Cal. Const. Article XIII A), your assessed value is your purchase price grown by no more than 2% a year — an "acquisition value" that, if you've owned a while, usually sits well below what the home would sell for today.

That changes how you appeal. A comparable-sales appeal in California is a Proposition 8 "decline-in-value" claim (Rev. & Tax. Code §51(a)(2)): it only wins if recent sales show your home's market value on the January 1 lien date is less than your current assessed value. If your comps land at or above that value, Prop 13 is already protecting you and there's no case to file.

Category	California
Assessment basis	Prop 13 acquisition value (purchase price + ≤2%/yr); appeal contests current market value
Appeal deadline	July 2 – Sept 15 or Nov 30, by county (§1603)
Where you file	County Assessment Appeals Board
Assessment cap	Prop 13: ≤2%/yr; Prop 8 relief is temporary
Can the board raise your value?	Yes, if the evidence supports it

One catch: a Prop 8 reduction is temporary. The assessor reviews it every year, so as the market recovers your assessed value can climb back toward your Prop 13 baseline — though it can never exceed your factored base year value. A decline-in-value win lowers this year's bill, not a permanent one.

Building your case

Because the whole question is whether your market value has dropped below your assessed value, the winning evidence is the same as anywhere: recent, nearby comparable sales — homes like yours that actually closed, not listing prices or online "Zestimate"-style guesses. One California-specific caution: the assessment appeals board is required by law to find your property's correct value, so it can raise your assessment as well as lower it. That's not a reason to avoid appealing — it's a reason to file only when your comps clearly support a lower value.

Filing at the county level

California's appeals run through your county assessment appeals board, and the mechanics — your county's exact deadline, whether it accepts an online filing, and its hearing schedule — vary across all 58 counties. We're building out county-specific guides (starting with the state's largest counties) with the exact filing office and local notes for each. Check back, or use PROppeal to generate your evidence now and confirm the filing logistics directly with your clerk of the board.

Get your case built

You don't need to wait on a county-specific guide to get started. PROppeal pulls licensed comparable sales for your address, checks them against your assessed value the way a Prop 8 decline-in-value case is actually judged, and gives you a straight answer on whether your assessment is out of line — before your county's deadline arrives.

Property tax rules and deadlines vary by jurisdiction and can change — verify with your county before relying on this.