How to file a decline-in-value review in Los Angeles County, step by step (2026)

By HiHolt · October 2026 · County forms and rules checked October 13, 2026

Short answer: File the Assessor's 2026 Decline-in-Value Review Application (Form RP-87), online or by mail, between July 2 and November 30, 2026. You need your 10-digit Assessor's Identification Number (AIN), your opinion of what your condo was worth on January 1, 2026, and, ideally, two sales of similar properties that sold as close to January 1, 2026 as possible and no later than March 31, 2026. The Assessor's review is free, and you can do every step yourself.

For why a condo can be assessed above its market value, see Proposition 13 vs. Proposition 8. For Downtown price trends, see Downtown LA condo prices fell. Did your property tax?

Who should consider it

The Assessor's test: you must show that on January 1, your property's market value was less than its current assessed value (Los Angeles County Assessor, Decline-in-Value). Condos qualify; the Assessor says all real property does. To see your 2026 assessed value, log in to the Assessor's online filing page or look up your property on the Assessor Portal. If similar condos sold near January 1, 2026 for less than that figure, you have the kind of evidence the Assessor asks for.

What you need

Step 1. Find your AIN and PIN

The AIN is your parcel number; the form calls it "Assessor's ID # (Map Book/Page/Parcel)" (2026 RP-87). The online filing page asks for the 10-digit AIN and the PIN "that appears on your Annual Property Tax Bill."

PINs come from the Treasurer and Tax Collector; without one, the Assessor suggests filing the paper form by mail (Assessor Portal FAQ). In a condo building, the Assessor's records may use a different address from yours; if an address search fails, the same FAQ suggests the portal's Map Search, your deed, or the Assessor's Help Desk.

Step 2. Choose two comparable sales

The Assessor calls sales of comparable properties "the best supporting documentation" and asks for two that sold "as close to January 1 as possible, but no later than March 31" (Assessor). On the 2026 form, the sale-date column reads "No later than 3/31/2026."

The limit comes from state law. Revenue and Taxation Code §402.5 requires comparable sales to be "sufficiently near in time to the valuation date," which "does not include any sale more than 90 days after the valuation date." For a decline-in-value review, the valuation date is January 1 (BOE Publication 30). Sales before January 1 can be used, but the BOE's guide says an appeals board will most likely view sales closer to the valuation date as more reliable, and the assessor adjusts each sale for price changes between the sale and the valuation date (Property Tax Rule 4).

What makes a sale comparable:

• Similar property. Section 402.5 asks for properties "sufficiently near" and "sufficiently alike in respect to character, size, situation, usability." The Assessor describes a property "similar in location, zoning, size, number of bedrooms and bathrooms, age, quality and condition to yours that sold in the open market."
• A real open-market sale. The BOE suggests checking that each sale was an arm's-length, open-market transaction; a sale between relatives, for example, may not be (Publication 30).
• For a condo, these tests usually point to units in your own building, or a similar building nearby, with about the same size, the same number of bedrooms and bathrooms, and a similar view.

Where to look: the Assessor's website and district offices have sales from the last two years; free websites and real estate or title agents also help (Assessor FAQ). The portal's recent sales include sales not yet verified, and its prices, converted from the documentary transfer tax, may end in a few extra dollars (Portal FAQ).

Step 3. Decide your opinion of value

The form asks for "Your Opinion of Value as of January 1, 2026." In California law, market value is what the property "would bring if exposed for sale in the open market" when neither buyer nor seller can take advantage of the other (R&T Code §110(a)). The BOE's guide describes a common method: compare each sale's price per square foot of living area, then adjust for differences from your property (Publication 30).

Step 4. File online or on paper

Online. Log in at the online filing page with your AIN and PIN to file, review an existing application, or see your 2026 assessed value and any 2026 review result. You can print what you entered at the end. The Assessor says some browsers may not work and recommends Microsoft Edge or Firefox. If you don't receive a confirmation within 48 hours, it asks you to mail the application (Assessor).

On paper. Download Form RP-87 (REV. 7/26) from the Forms tab of the Assessor's Decline-in-Value page; the PDF has fill-in fields. Attach supporting information, sign, keep a copy, and mail it to: Los Angeles County Assessor, 500 West Temple Street, Room 286, Los Angeles, CA 90012-2770 (2026 RP-87).

When. The 2026 form "MUST be filed between July 2 and November 30, 2026," mailed applications "are valid if postmarked by November 30, 2026," and applications received outside those dates cannot be processed. For help, the form lists 213-974-3211 and 1-888-807-2111.

Step 5. After you file

An Assessor appraiser reviews your form and evidence and may also consider other sales information. If the January 1 market value is below your trended base value (your Proposition 13 value), your assessed value is lowered to market value for the fiscal year beginning July 1, and "the adjusted value will be reflected on your annual tax bill." If market value is higher, nothing changes (Assessor).

You can check the status online, where the filing page shows any 2026 review result; for details, the Assessor says to contact your District Office. Neither the Assessor's page nor the form says how long a review takes. The 2026 form asks you to keep a copy "as a reminder to file an assessment appeal if you do not receive the Assessor's findings by October 1, 2026," and says you may appeal "without waiting for a response to this claim."

Filing does not postpone your tax bill: the BOE says to pay according to the bill you received, or penalties and interest apply (BOE FAQ).

If you disagree with the result

You may file an appeal with the Assessment Appeals Board, a separate process; see Assessor review or Assessment Appeals Board? for how the two compare. Filing with the Assessor does not extend the board's filing period: the Assessor says that to preserve your right to a formal appeal, you must file with the board between July 2 and November 30, and that an appeal "is separate from the informal review" (Assessor, Contesting Your Assessed Value).

FAQ

Where do I find my AIN? On your annual property tax bill, or through an address search on the Assessor Portal (see step 1 if your condo's address doesn't come up).

What comparable sales can I use for a Prop 8 review? Open-market sales of similar properties, ideally in your building or nearby, as close to January 1, 2026 as possible and no later than March 31, 2026.

Can I file without comparable sales? Yes. The Assessor says such applications are accepted and processed, though sales help.

How long does the Assessor take? The Assessor's Decline-in-Value page and form don't say. You can check status online, and you may appeal without waiting for the answer.

Does the Assessor charge a fee? No. California law describes the Assessor's informal review as available "at no cost" (B&P Code §17537.9), and the 2026 form lists no fee.

About HiHolt

This paragraph describes our own paid service. You do not need a company for any step above. HiHolt prepares and files Proposition 8 decline-in-value reviews for California condo owners who sign a written authorization. Downtown Los Angeles condos are checked online right away; other California condos on request. The fee is 30% of the property tax actually saved for that year. Nothing is charged before filing, HiHolt pays Los Angeles County's $46 appeal fee, and you pay only if your tax goes down. HiHolt is a brand of Fortunewoods LLC, a private company. Its filings are made under Los Angeles County Tax Agent Registration Number AG00000-1565.

Required notice

This service is not associated with any government agency. An informal assessment review by the Assessor is free of charge, and you can file an Application for Changed Assessment with the Assessment Appeals Board on your own behalf. The appeals board also has the authority to raise property values, but in no case higher than the Proposition 13 protected value.

County forms, County pages and state law checked October 13, 2026. This article describes the 2026 filing period in Los Angeles County and is not legal or tax advice.

Sources:

• Los Angeles County Assessor, Decline-in-Value page (General Info, FAQ, Forms, Status and Application tabs), checked October 13, 2026: assessor.lacounty.gov
• Los Angeles County Assessor, 2026 Decline-in-Value Review Application, Form RP-87 (REV. 7/26), checked October 13, 2026: res.cloudinary.com
• Los Angeles County Assessor, Decline-in-Value online filing, checked October 13, 2026: assessor.co.la.ca.us
• County of Los Angeles newsroom, Assessor's release "Decline-in-Value Review Forms Available Now" (July 30, 2026), checked October 13, 2026: lacounty.gov
• Los Angeles County Assessor, Contesting Your Assessed Value, checked October 13, 2026: assessor.lacounty.gov
• Los Angeles County Assessor Portal and its FAQ, checked October 13, 2026: portal.assessor.lacounty.gov and portal.assessor.lacounty.gov
• California Revenue and Taxation Code §402.5, checked October 13, 2026: leginfo.legislature.ca.gov
• California Revenue and Taxation Code §110, checked October 13, 2026: leginfo.legislature.ca.gov
• California State Board of Equalization, Property Tax Rule 4, "The Comparative Sales Approach to Value," checked October 13, 2026: boe.ca.gov
• California State Board of Equalization, Publication 30, "Residential Property Assessment Appeals" (February 2020), checked October 13, 2026: boe.ca.gov
• California State Board of Equalization, Decline in Value FAQs, checked October 13, 2026: boe.ca.gov
• Los Angeles County Assessment Appeals Board, checked October 13, 2026: lacaab.lacounty.gov
• California Business and Professions Code §17537.9, checked October 13, 2026: leginfo.legislature.ca.gov