How a Proposition 8 reduction works
Every procedural fact on this page traces to an official form or to a county or state publication, and the statutory text behind each rule sits one click away, verbatim and untranslated. Where we could not verify a point against a primary source, we label it unverified rather than filling in an assumption.
Sources are listed one by one on the sources page.
The whole process, end to end
- 1Valuation
- 2One signature
- 3Both filings, prepared
Both go in on the same day; both close 7/2 – 11/30
- 4County reviews and decides
- 5Our fee only if the assessment comes down
Each step below opens to the rule and the statutory text behind it.
California property tax, in five rules
Each rule states its conclusion first, then what follows from it, then the citation. The statutory text sits under the rule it supports, verbatim and in English, one click away.
Proposition 13 anchors an assessment to the last purchase, then trends it upward.
A base year value is fixed at the last change of ownership or new construction. Every year after that it is compounded by an inflation factor that may not exceed 2 percent. The factor is published by the State Board of Equalization and applies statewide; it does not respond to conditions in any local market. For the 2026 lien date the Board measured California consumer price growth well above the ceiling and directed assessors to apply the 2 percent maximum, as it had in each of the four preceding assessment years.
Cal. Revenue and Taxation Code §51(a)(1)(D) · BOE Letter to Assessors No. 2026/002
Statutory text and the Board's instruction
An assessment does not fall because the market fell.
On every lien date the taxable value is required by statute to be the lesser of the factored base year value or current market value. The lower of the two reaches the roll only once the Assessor has reviewed the assessment and enrolled it. Until that review happens, the higher value stays on the roll, and your bill is computed from it. Nothing in the sequence starts on its own.
Cal. Revenue and Taxation Code §51(a) · State Board of Equalization, Decline in Value
Statutory text and the Board's definition
The last two passages both come from the Board's decline-in-value page, but they are separate paragraphs there, about nine hundred characters apart. The text between them, which defines the base year value, is omitted.
Proposition 8 sets no minimum gap.
Proposition 8 permits a temporary reduction when real property declines in value, and is codified at Revenue and Taxation Code §51(a)(2). That paragraph sets no threshold of any kind: a market value below the factored base year value on the lien date qualifies, whatever the size of the difference. A case is decided on the evidence filed, not on the width of the gap.
Cal. Revenue and Taxation Code §51(a)(2)
Statutory text
No threshold is applied on this site either. An internal screen that hid any unit not assessed at least fifteen percent above the market estimate was removed on September 15, 2026, because no basis for it could be found in the statute or in any county publication. Every real figure is now shown.
A Proposition 8 reduction is temporary and is reviewed every year.
A value reduced under Proposition 8 is re-examined by the Assessor on each following lien date. While a property remains in decline-in-value status its assessed value may rise by more than the 2 percent ceiling that applies under Proposition 13, but it can never be carried above the existing factored base year value. The base year value itself is not changed by a reduction, and a later recovery in the market restores the assessment only as far as that ceiling.
State Board of Equalization, Decline in Value
The Board's statement, verbatim
Three dates, all set by the county.
Value is measured on the January 1 lien date. Comparable sales must have recorded no later than March 31: Revenue and Taxation Code §402.5 rules out any sale more than ninety days after the lien date, and the RP-87 form fixes that boundary at 3/31, so a sale recorded in April is not considered, however well it makes the point. That is the hard boundary comparable sales are screened against here. Both routes are filed inside the same window, which closes on November 30. Where that date falls on a Saturday, Sunday or legal holiday, Property Tax Rule 305(d)(6), the appeals board and the Assessor's own filing portal all treat an application mailed and postmarked on the next business day as timely; in 2026 November 30 is a Monday, so no extension applies.
Lien date 1/1 · comparable sales no later than 3/31 · filing window 7/2 – 11/30 · RP-87 (REV. 7/26) · Cal. Revenue and Taxation Code §402.5
The three dates on the forms, verbatim
RP-87 provides space for exactly two comparable sales. A third sale, and any further evidence, belongs in the evidence packet attached to the application rather than compressed into the form.
Two filings, one deadline
The county provides two independent routes and both are used. The two windows close on the same day.
| RP-87 (Assessor review) | AAB-100 (Assessment Appeals Board) | |
|---|---|---|
| Nature | Informal internal review | Formal, quasi-judicial, binding |
| County fee | None | $46, non-refundable |
| Window | 7/2 – 11/30 | 7/2 – 11/30 |
| Hearing | None | Yes |
| How evidence is submitted | With the application, to the Assessor | Not with the application. Through the AAP portal, which opens only once the case is scheduled; the deadline is the one stated in the scheduling notice |
| Withdrawal | Not applicable | Permitted, without penalty |
Treating the free route as a first attempt, with an appeal held in reserve. Both windows close on the same day. If you are still waiting on the Assessor in November, you have lost the appeal window too, and the assessment year is gone. RP-87 states the point on its own face: You may appeal before the applicable deadline without waiting for a response to this claim. The correct sequence is to file both on the same day.
Two further points on evidence and withdrawal, and what October 1 is
EXM-202 states on its face that the appeals board is a separate agency from that of the Office of the Assessor, the Auditor-Controller, and the Treasurer and Tax Collector. Evidence is therefore submitted twice, once to each office, rather than filed once and relied on in both places. That duplication is our work, not yours.
Verbatim from RP-87: You may withdraw your AAB appeal without penalty, for any reason. Withdrawal should wait until the reduction the Assessor agreed to has actually been enrolled. Withdraw earlier and you can end up with neither.
October 1 is a checkpoint printed on the form, not a deadline. It marks the date by which the Assessor's findings would normally have arrived; the statutory deadline is November 30.
Authorization and agency in Los Angeles County
What a tax agent may and may not do here
This point took the longest to establish, and it is rarely written down anywhere. The answer is counterintuitive. The Assessor's online decline-in-value portal states in writing that tax agents cannot file through it. The paper RP-87 has always carried an agent block, and an Agent Signature line alongside the Owner Signature. The appeals board operates a login built specifically for agents. What is closed is one channel, not the agency relationship.
The three source texts: Assessor online portal / RP-87 / lacaab.lacounty.gov
The Assessor's online portal states in writing that tax agents cannot file online.
The paper RP-87 carries an Agent/Company Name field and its own Agent Signature and date line. The Assessor plainly contemplates an agent filing the paper review request on an owner's behalf.
The appeals board built a login for agents. The Assessor's online portal has none. Two different doors.
The repeated word in “To file online online” is how the sentence is published on lacaab.lacounty.gov. County text is reproduced here without correction.
EXM-202 states on its face that the form is not valid without a current Tax Agent Registration Number, unless one of the exclusions under Los Angeles County Code Section 2.165.010(G) applies. Until that number is issued, what you get is the valuation, the evidence packet, and the forms completed up to the signature line, which you sign and file, rather than a filing made by an agent. The service agreement says the same.
One signature, four documents: three authorizations and one service agreement
In Los Angeles County the Assessor and the appeals board are separate offices that do not share files, and the authorizations are two separate sets. A single signature produces all four at once:
| Document | Who it binds | How long it lasts | Why it is needed |
|---|---|---|---|
| EXM-202 Part II | Assessor / Auditor-Controller / Treasurer-Tax Collector | 4 years from the date of execution | Covers the RP-87 route. Verbatim from the form: Agent has full authority to handle all assessment matters with your office. |
| AAB-102 | Assessment Appeals Board | Up to 4 consecutive calendar years | Authorizes the agent to sign and file the appeal application. First filing only. |
| Rule 305 authorization | General written authorization | As above | Carries all six elements of Property Tax Rule 305(a)(1). BOE Annotation 180.0006: no prescribed form is required. This is the document §17537.9(e) requires to be attached. |
| Service agreement | Between you and us | The authorized years stated in it; ends earlier if you revoke the authorization in writing or the property changes ownership | Sets out the contingency percentage, when we are allowed to bill at all, and how the engagement is canceled. |
Two footnotes on those four documents, with the underlying text
Verbatim from the form: This form may only be used for an Assessment Appeal by a taxpayer who has already filed an application. It is therefore issued separately, once the AAB-100 has been filed and an Application Number has come back. It governs changing agents, withdrawing, and settling value with the Assessor.
The scope may be written as every parcel and assessment within Los Angeles County, so several units need only one signature. Retroactive authorization is not permitted: you cannot sign now for a year that has already closed.
How the market estimate is produced
The valuation takes every condominium unit in the coverage area, 103,653 of them, one at a time, as of the January 1 lien date. Up to four independent methods are run for each unit, as many as the recorded sales will support. Where at least one method runs, the unit page shows how the estimate compares with the assessed value and which kinds of evidence it rests on, and the comparable sales themselves go into the evidence filed with the Assessor and the board; where none can, no estimate is published, and the note below gives the count.
Results are published at three settings, conservative through aggressive, and the site shows the central figure by default. Where the methods disagree materially the unit is flagged on its own page, because a wide spread is a statement about the evidence rather than about the property. The methods themselves, and the adjustments inside them, are not published: they are our work product. The filing stands or falls on the comparable sales, and those are published in full.
Of 103,653 units, 13,090 (12.6%) support no method at all, and for those no estimate is published. 57.5% of them are units whose identifier cannot be resolved against the building record. In that case the page says the value cannot be computed, rather than showing a made-up figure.
The calendar
The dates are the county's, not ours.
- 1. Intake, valuation, authorization
We confirm the AIN against the roll value, produce a value opinion as of January 1 with the comparable sales behind it, and you sign once. A copy of the authorization goes in with the filings.
- 2. File during 7/2 – 11/30, both on the same day
RP-87 to the Assessor at no county charge, and AAB-100 to the appeals board with the $46 fee. November 30 is the statutory deadline; October 1 is only a checkpoint printed on RP-87.
- 3. Assessor decision / board scheduling and hearing
The Assessor either reduces or confirms the value; if you disagree, the appeals board route continues. Once the board schedules the case, evidence goes through the AAP portal, and the deadline is the one stated in the scheduling notice — check it as soon as the notice arrives.
- 4. Closed
The reduction is enrolled, the value is confirmed, or the appeal is withdrawn. We track case progress by stage and show it only to the owner of record: in your account after you sign in, or through the case portal with your case number and the email you signed with.
Start with a unit address
The lookup, the valuation and the signature are free, and you pay nothing at that stage. Under Cal. B&P §17537.9(c), no offeror of an assessment reduction filing service may charge, demand or collect any money before the application has been filed with the Assessor or with the clerk of the assessment appeals board.