If your California property’s market value on January 1 is lower than its assessed value, the county assessor must tax you on the lower value. You ask for it with a free “decline-in-value” (Prop 8) review, and in Los Angeles County the 2026 window runs July 2 through November 30. No lawyer or fee is needed. Here’s how it works.
What Prop 8 does
Under Prop 13, your assessed value starts at your purchase price and can rise no more than 2% a year. That’s your “factored base year value.” Prop 8 adds a safety valve: if the market drops below that number, the assessor enrolls the lower market value instead.
Sacramento County’s assessor puts it simply: Prop 8 “amended Prop 13 to recognize declines in value for property tax purposes.” The test date is January 1, the lien date. The question is: could your property have sold for less than its assessed value on that day?
Prop 8 is most likely to help if you:
- bought near a market peak (for example 2021–2022)
- own a home, condo or rental in an area where prices have softened since you bought
- own a property with problems the county doesn’t know about: an original kitchen, a failing roof, foundation work, a busy road
Step 1: Check your numbers
Find your assessed value on your tax bill or the assessor’s website. Then look up recent sales of similar homes near you, ideally close to January 1. Sacramento County notes that appraisers “are required to use open market sales that occurred reasonably close in time to the January 1 lien date,” and before the following March 31.
If similar homes sold for clearly less than your assessed value, you likely have a case. Our guide to finding comparable sales walks through it.
Step 2: File the review request
Each county runs its own informal review. Examples:
| County | How to ask | When |
|---|---|---|
| Los Angeles | Decline-in-Value Review Application (Form RP-87), online or by mail | July 2 – November 30 |
| Sacramento | Prop 8 review with the Assessor (call or email the office) | During the county’s filing period |
| Riverside | “Request for Review” on the Assessor-County Clerk-Recorder website | Early filing encouraged; final deadline November 1 in 2026 |
The review is free. Sacramento calls it “an informal process conducted by the Assessor’s Office that is free of charge.” Include your best sales, photos of anything that hurts value, and any repair bids.
Step 3: Wait for the result (and protect your appeal rights)
The assessor reviews your evidence and mails a result. If the value is lowered, your next tax bill uses the lower number.
Watch the calendar, though. An informal review does not extend your deadline to file a formal appeal. Sacramento warns that if the assessor finishes after the appeal deadline, you have no further appeal unless you’d “already filed a separate assessment appeal” by then. In most counties that deadline is November 30. In 11 counties, including Alameda, San Francisco, Santa Clara and Ventura, it’s September 15.
If the review is denied, or you disagree with the result, file a formal Assessment Appeal Application with your county’s appeals board before that deadline. Some counties charge a filing fee (Sacramento: $30). Our California appeal guide covers the formal appeal step by step.
Step 4: Know that it’s temporary
A Prop 8 reduction is temporary. The assessor reviews it every year, and as the market recovers your value goes back up, faster than 2% a year if needed, until it reaches your factored base year value again. Los Angeles County notes owners “may see their property taxes increase by more than two percent” during that recovery. It never goes above your Prop 13 value.
That’s why it pays to check every year while your value is reduced.
Doing it yourself vs. getting help
You can do every step yourself for free. If you’d rather not track sales, deadlines and county forms, Recoup Capital files the review and, if needed, the formal appeal for you. You pay 30% of what you save, and nothing if your value doesn’t go down. Start a free review.
Sources: Los Angeles County: Decline-in-Value Review forms available now (July 30, 2026), Sacramento County Assessor: Prop 8 Decline in Value, BOE: 2026 assessment appeals filing periods. Rules and dates vary by county; confirm with your assessor.