How to Appeal Your San Francisco Property Tax Assessment

If your San Francisco property is assessed for more than it is currently worth, you can appeal to have the assessment, and your property tax bill, temporarily reduced. This is done under Proposition 8, which allows a decline-in-value reduction when a property's market value falls below its assessed value. The formal appeal window runs from July 2 to September 15 each year, with a $120 filing fee paid to the Assessment Appeals Board. The key to a successful appeal is strong comparable sales that show your property's true market value. This guide walks through how it works.

Key Findings

• Proposition 8 lets you get a temporary assessment reduction when your market value has fallen below your assessed value.
• The formal appeal window is July 2 to September 15 each year, with a $120 fee to the Assessment Appeals Board.
• Single-family owners can also request an informal review from January 2 to March 31.
• Your case is built on comparable sales that reflect your property's value around the January 1 lien date.
• A reduction is temporary: the assessment can rise again, up to the Proposition 13 cap, as the market recovers.

What Is a Proposition 8 Assessment Appeal?

California's Proposition 13 caps how much your assessed value can rise each year, but Proposition 8 works in the other direction: when your property's current market value drops below its assessed value, you can ask the county to temporarily lower the assessment to match. A lower assessment means a lower property tax bill. It is most relevant after a market softens, or when a specific assessment simply runs higher than recent sales support. San Francisco explains the basics on its decline-in-value page.

When Is the Deadline to Appeal in San Francisco?

There are two paths. Single-family residential owners can request an informal review from the Assessor between January 2 and March 31. Separately, all property owners can file a formal appeal with the Assessment Appeals Board between July 2 and September 15. The formal application carries a $120 non-refundable fee and must be submitted or postmarked by September 15 to be considered timely. Missing that date generally means waiting until the next year, so the deadline matters.

How Do I Build a Strong Case?

An appeal succeeds or fails on evidence, and the best evidence is comparable sales. You want recent closed sales of similar properties, ideally in your own building or immediate area, that show a market value below your assessed value around the January 1 lien date. Adjust for differences in size, floor, view, and condition. Clean, verifiable comparables pulled from the MLS are far more persuasive than general market commentary, because the appraiser and the board can check every line.

Here is an illustrative comps grid for a downtown high-rise condo assessed at $1,150,000, using anonymized closed sales near the January 1 lien date. This is a simplified example of how the evidence is organized:

The three closed sales cluster around $890 per square foot, pointing to a market value near $985,000, well below the $1,150,000 assessment. That gap, roughly $165,000, is the basis for requesting a temporary reduction. Every figure traces to a verifiable MLS record the board can confirm. Adjustments for floor, view, and condition refine the picture, but the core of the case is simply that similar units sold for less.

What Happens After I File?

After you file the formal application, the Assessment Appeals Board schedules a hearing. You present your evidence, the Assessor presents theirs, and the board decides on a value. If your comparables are strong and well organized, the case is straightforward. Preparation and documentation are what carry the day.

Is the Reduction Permanent?

No. A Proposition 8 reduction is temporary. As the market recovers, the Assessor can raise your assessed value again in future years, up to what it would have been under the Proposition 13 cap. So an appeal lowers your bill now, but it does not permanently reset your assessment.

From experience: I recently helped a downtown high-rise owner assemble a comps-based case to challenge an over-assessment. We built it around the building's actual closed sales, pulled straight from the MLS so the city could verify every line, and worked to file ahead of the September 15 deadline. I am a real estate specialist, not a certified tax professional, so I focus on what I do best, the accurate market data and comparables, and leave the tax and filing specifics to the owner and their advisor. That combination, strong comps plus the right professional, is what makes a case credible.

A Note

This article is general information, not tax or legal advice, and deadlines, fees, and procedures can change. Confirm the current details with the San Francisco Assessor-Recorder or the Assessment Appeals Board, and consult your tax advisor about your specific situation.

Frequently Asked Questions

Can I appeal my San Francisco property tax assessment?

Yes. Under Proposition 8, if your property's market value has fallen below its assessed value, you can appeal for a temporary reduction and a lower tax bill.

What is Proposition 8?

It is the rule that allows a temporary reduction in assessed value when market value drops below the assessed value, the reverse of Proposition 13's upward cap.

When is the deadline to appeal in San Francisco?

The formal appeal window is July 2 to September 15 each year. Single-family owners can also request an informal review from January 2 to March 31.

How do I prove my property is over-assessed?

With comparable sales of similar properties, ideally in your building or area, that show a market value below your assessed value around the January 1 lien date.

Does the reduction last forever?

No. It is temporary. The assessment can rise again in future years as the market recovers, up to the Proposition 13 cap.

What does it cost to appeal?

The formal application carries a $120 non-refundable filing fee paid to the Assessment Appeals Board.

Work With Sean Mamola

Think your San Francisco home is over-assessed? The foundation of a strong appeal is credible comparable sales, and that is exactly where a local specialist helps. Sean Mamola brings 17+ years of real estate expertise and deep knowledge of San Francisco's buildings and closed-sale data, and can prepare the comparables that support your case. As a Global Luxury Specialist with Compass, Sean provides the market evidence; your tax advisor handles the filing. Schedule a consultation or call (415) 704-3640.