A property tax appeal appraisal shows what your home was worth on January 1, the date California uses to set assessed values. If that market value is lower than the assessed value on your tax bill, the appraisal is the evidence you file with the Assessor or the Assessment Appeals Board to ask for a lower assessment. RealVals prepares these reports for homeowners in San Francisco and Marin County.
How assessed value works in California
Under Proposition 13, your assessed value starts at the purchase price and can rise by no more than 2% a year. That cap protects owners when prices climb. It does nothing for you when prices fall, because the assessed value keeps creeping up even as the market slips.
Proposition 8 covers that gap. When the market value of a property on January 1 is lower than its factored base year value, the Assessor must enroll the lower number for that year. The cut is temporary. The Assessor reviews the value every January 1, and it can climb back by more than 2% a year until it reaches the Prop 13 value again.
When an appraisal makes sense
A Prop 8 claim usually comes up in one of these situations:
- You bought near a market peak and prices in your neighborhood have since dropped
- Condos or units in your building have sold for less than your assessed value
- The property has condition problems a sale price at purchase did not reflect
- Your assessed value went up after a remodel and the market has softened since
A quick test helps before you pay for anything. Look up a few recent sales of homes like yours that closed close to January 1. If they point to a value clearly below your assessed value, an appraisal can document the gap. If they do not, an appraisal will probably say the same thing.
Why the January 1 date matters
Both counties judge your claim on market value as of January 1, which is the lien date. A tax appeal appraisal is therefore a retrospective appraisal: the inspection happens now, but the value is set as of that earlier date. The appraiser uses comparable sales that closed around January 1. San Francisco, for example, will not consider sales that closed after March 31 in an informal review.
San Francisco deadlines
- Informal review: owners of single-family homes can ask the Assessor-Recorder for a decline-in-value review from January 2 to March 31. The review is free, and results arrive with the Notice of Assessed Value in July.
- Formal appeal: any property owner can file with the Assessment Appeals Board from July 2 to September 15. The Board charges a filing fee.
If the informal review does not go your way, or you missed March 31, the formal appeal window still applies. Details are on the city's decline-in-value page.
Marin County deadlines
- Informal review: the Marin Assessor accepts Prop 8 decline-in-value requests from July 1 to October 31.
- Formal appeal: if the issue is not resolved by November 1, you can file with the Assessment Appeals Board from July 2 to November 30.
Marin explains the process on the Assessor's decline in value page. In both counties, a supplemental assessment after a purchase or new construction has its own deadline, usually within 60 days of the notice.
Can you appeal without an appraisal?
Yes. Neither county requires one, and many owners file with a few sales they found themselves. That works when the drop is obvious. It gets harder when your home is unusual, sales are thin, or the Assessor picks different comparables than you did. A signed report from a California certified appraiser explains why each sale was chosen and how it was adjusted, which gives the Assessor or the Board something concrete to weigh.
A rough way to size the stakes: California's base property tax rate is 1% of assessed value, before local bonds and charges. If your home is assessed at $1,100,000 and was worth $950,000 on January 1, the $150,000 gap is worth at least $1,500 a year in base tax. Local add-ons push the real number higher.
What the report includes
Austin Fernald inspects the property, sets the effective date to January 1 of the year under appeal, and selects sales from that period. The report describes the home, explains each comparable and adjustment, and states a market value you can attach to the application. If you need a current value for another reason, such as a sale or refinance, that is a separate assignment with today's date.
Cost and turnaround
RealVals fees for tax appeal appraisals start at $500 for a single-family house, condo or land, and $700 for a 2 to 4 unit building. Larger or more complex properties are quoted individually. Most reports are delivered within 4 to 5 business days after the inspection. See pricing for the full fee list, or request a free quote with your address and the county you are appealing in.