Assessment Appeals - The Deadline Nobody Tells Owners About

Every year, San Diego County opens a five-month window in which property owners can formally challenge the assessed value their tax bill is built on. Every year, it closes with most owners never having looked at whether they had a case.

This year the window closes Monday, November 30, 2026.

For multifamily owners, this cycle is worth more attention than usual - not because the process changed, but because the economics did. If your insurance premium jumped, your operating costs climbed, and your net operating income is meaningfully below what it was when you bought, there is a reasonable chance your property is assessed above its current market value. That gap is money, and nobody at the County is going to point it out for you.

Why Multifamily is Different

Most articles about assessment appeals are written for homeowners, and they tell you to pull comparable sales. That advice is incomplete for an apartment building.

Income-producing property is valued differently. An assessor looking at a 40-unit building is looking at what the building earns - rents, vacancy, operating expenses, and the capitalization rate a buyer would apply to that income. Comparable sales still matter, but they are one input rather than the whole analysis.

This matters because of what has happened to San Diego operating costs over the past few years. As we covered in our post on the California insurance squeeze, premium increases on multifamily assets here have been severe, and they have landed on top of rising utility, maintenance, and labor costs. Meanwhile, allowable rent growth on covered units is capped- the AB 1482 limit for San Diego County dropped to 8.2% for increases effective August 1, 2026, and in practice most stabilized properties are achieving well below the cap.

Costs up, revenue growth constrained. That is NOI compression, and on an income approach it flows directly into value. An owner can be sitting on a property whose assessed value reflects a stronger income stream than the one the building actually produces today.

What You Are Actually Appealing

Two things are worth separating.

Your base year value is set when you buy, and under Proposition 13 it rises by no more than 2% a year thereafter. If you purchased in 2021 or 2022 at the top of the market, your base year value is that purchase price, escalated.

Your current market value is what the property would sell for now. Under Proposition 8, when market value falls below the factored base year value, you are entitled to have the lower figure used - temporarily, for as long as the condition lasts.

That temporary reduction is what most multifamily owners in this position are actually pursuing. And it is worth knowing that it does not renew itself. A Prop 8 reduction is reviewed annually, and the full Prop 13 value can be restored without a separate notice to you. If you received a reduction in a prior year and assumed it was permanent, that assumption is worth checking.

San Diego County's 2026 assessment is tied to a January 1, 2026 lien date. That is the date your evidence needs to speak to, not today's conditions, and not last summer's.

How to Tell Whether You Have a Case

Before spending time on paperwork, run a rough check. You are looking for a gap between assessed value and defensible current market value.

Pull three things:

1. Your current assessed value, from your tax bill or the Assessor's records.
2. Your trailing twelve months of actual operating results - real collected revenue, real expenses, including the current insurance premium rather than the one you were paying two years ago.
3. A defensible capitalization rate for your submarket and asset class as of early 2026.

Divide your trailing NOI by that cap rate. Compare the result to your assessed value. If the assessed value is higher by a margin that matters - and for most owners, "matters" means enough to justify the effort and any professional fees - you have something worth a closer look.

You are the strongest candidate for an appeal if you bought in roughly 2021 through 2023, if your insurance renewal has materially reset your expense base, or if your property has carried persistent vacancy or credit loss that isn't reflected in a market-rate rent roll.

You are a weaker candidate if you have owned for many years. A long-held building's factored base year value is often far below current market value, and no amount of NOI compression closes that gap.

The Process, in Plain Terms

The County publishes a ten-step guide, and it is worth reading in full. The parts that trip owners up:

Talk to the Assessor before you file. The Assessor's Office will explain the basis for your assessment and review information you bring. If there is a factual error - wrong unit count, wrong square footage, an improvement that was never built - it can sometimes be corrected without a formal appeal.

File on paper, and mind the postmark. The Assessment Appeal Application must be mailed or delivered in person to the Clerk of the Board of Supervisors, Assessment Appeals.  Applications received by mail are deemed received based on the USPS postmark. Use tracking and keep proof. You should receive a confirmation postcard from the Clerk within two weeks; follow up if you do not.

Keep paying your property taxes. Filing an appeal does not suspend your obligation. Pay the bill. If your appeal succeeds, the Auditor processes the refund automatically.

Most appeals settle before a hearing. If you and the Assessor reach agreement on value beforehand, that written stipulation goes to the Appeals Board and you never present. You can also request an "exchange of information" , where both sides trade the evidence they intend to present - any time more than 30 days before your hearing. For an owner with clean operating statements, that exchange is often where the matter resolves.

If you do get a hearing date, confirm your attendance. You'll be notified at least 45 days ahead, and you or your agent must confirm attendance at least 21 days before the hearing date. Miss that confirmation and the hearing can be pushed. Fail to appear at all and your application can be denied outright.

Two Risks Worth Knowing

Assessment appeals are low-drama, but they are not risk-free.

The Board can raise your assessment, not just lower it. It decides value based on the evidence in front of it, and that evidence can cut against you. If your rent roll shows you are achieving more than the Assessor assumed, filing an appeal is how you tell them. This is the single best argument for having someone competent look at your numbers before you file rather than after.

Timing is slow. Appeals are expected to be heard and decided within two years of filing. That is a long tail on an operating decision, and it is worth understanding the mechanics, including what happens if the two years lapse - before you begin.

What To Do In The Next Thirty Days

If you own multifamily in San Diego County and haven't looked at this:

• Pull your current assessed value and your trailing twelve months of actuals.
• Run the rough NOI-over-cap-rate check above.
• If there's a gap, call the Assessor's Office and ask what income and expense assumptions underlie your assessment. That conversation is free and frequently clarifying.
• If the gap holds up, engage a property tax agent or attorney who handles income-property appeals. Build the evidence file - rent roll, operating statements, insurance renewal documentation, comparable sales, vacancy history - and file well before November 30.

Do not wait until late November to file since comps and operating documentation take time to assemble.

Southwest Equity Partners manages approximately 2,700 apartment units across San Diego County. We are not property tax agents or tax counsel, and nothing here is legal or tax advice - but we do help owners assemble the operating data an appeal requires.

👉If you'd like a second set of eyes on whether your assessment looks defensible, get in touch wth us .