A property tax appeal appraisal shows an assessment appeals board one thing: an independent opinion of the property's market value as of the valuation date, which for a decline-in-value appeal is the January 1 lien date, with the facts and the closed sales that support it laid out so they can be checked. The county's assessed value is not an appraisal; it is the value the Assessor enrolled under California's assessment rules. The board weighs the appraisal beside the Assessor's evidence and decides what value goes on the roll. The report informs that decision; it does not make it.
For how the two counties on either side of Mills Avenue handle appeals, start with the guide to property tax appeals on the Los Angeles and San Bernardino county line.
What does an assessment appeals board decide?
An assessment appeal, a formal request to the county's appeals board to change the value the Assessor enrolled, is heard as an evidence session. The Los Angeles County Assessment Appeals Board describes itself as acting in a quasi-judicial capacity to settle valuation disputes between taxpayers and the Assessor's Office. The San Bernardino County Clerk of the Board says that after considering the evidence presented, its board or hearing officers may determine that the value should be decreased, increased or remain the same.
An appeal opens the value; it does not set a direction. The State Board of Equalization's guide for residential appeals adds that the board considers only the evidence the owner and the Assessor present at the hearing, not material attached to the application. An appraisal report puts the owner's evidence in a form the board can examine line by line.
What does the report state before it states a value?
Before any sale is discussed, the report identifies the assignment.
- The property. The address and the assessor's parcel number.
- Intended use. Intended use, what the report will be used for: evidence of market value in a property tax review or appeal.
- Intended users. Intended users, the people entitled to rely on the report: usually the owner who orders it.
- Effective date. The effective date, the date the opinion of value applies to. For a decline-in-value appeal that is the January 1 lien date of the year under appeal. Why the effective date is the lien date covers the reasoning and the other valuation dates.
- Definition of value. California's Revenue and Taxation Code section 110 defines full cash value, the price the property would bring in an open-market sale between informed parties, neither able to take advantage of the other. A report for this use names that definition.
- Scope of work. The scope of work, the type and extent of research and analysis: whether the interior was inspected, which records were checked and how far the sales search reached.
How does the report describe the house as it stood on January 1?
The board is asked about the house on the lien date, not on the day of the inspection. The report measures gross living area, the finished space above grade, rather than copying it from public records, and lists additions, conversions and any ADU with their permit history, because what legally existed on January 1 is part of the question.
Condition is where dates matter most. If the roof was failing on January 1 and was replaced in March, the inspection will show a new roof. The report then relies on dated photographs and invoices and states an extraordinary assumption, an assumption about uncertain facts that, if false, could change the result: that the condition on the lien date was as those records show.
Which sales does the board expect to see?
The State Board of Equalization's guide says that in most residential appeals the most reliable evidence of market value is the sale of similar properties, and it sets out three tests a board applies to each one.
- Was it an arm's-length, open-market sale? Exposed to the market, available to any buyer, between parties who were not related and not under pressure.
- Is it physically similar? Distance, zoning, bedrooms and bathrooms, year built, living area, lot size and view, pools and patios, quality and condition.
- Is it relevant to the valuation date? The guide states that comparable sales dated more than 90 days after the valuation date cannot be admitted, and that sales closer to the date are usually viewed as more reliable.
An appeal appraisal applies those tests first. Each sale carries its date, its source and a written reason it was chosen; a sale that fails the timing test is left out.
Why are adjustments shown rather than implied?
The guide notes that owners often compare price per square foot of living area, and that the party presenting sales must be ready to discuss the differences and adjust for them. Price per square foot alone does not do that. A Claremont ranch house north of Foothill Boulevard with a converted garage and a smaller lot is not the same house as one with an intact garage on a larger lot, even at the same living area.
The report therefore shows each adjustment, for size, condition, lot, location and features, and the market evidence behind it. The reconciliation explains which sales carried the most weight. A board member can disagree with a step, but can see every step.
What changes when the closest sales are across the county line?
Mills Avenue is Montclair's western boundary and the line between Los Angeles and San Bernardino counties. A postwar house on the Claremont side may have its closest similar sales in Montclair, assessed by a different county and recorded under different conventions. Those sales can be used, but the report has to say why each was chosen, how the location differs and what adjustment the market supports for that difference. What the county line does to comparable sales explains how that is tested, and the Claremont area page describes the pockets on the Los Angeles County side.
The same applies to a house in Montclair or Upland valued against Claremont sales.
What the report does not do
- It does not predict what the board will decide, and nothing is said about the value before the work is done.
- It does not advocate. The appraiser is independent of every party, including the owner who orders the report, and the fee does not depend on the value.
- It does not file anything. Filing periods are set by each county; confirm the current period on the Los Angeles County Assessment Appeals Board page or the San Bernardino County Clerk of the Board page.
- It does not replace the hearing. A board may require the person who prepared a report to be present to answer questions. Whether that is part of the assignment is agreed before work begins, and an appraiser who appears explains the report; he does not represent the owner.
An online estimate, an agent's comparative market analysis and a cash offer are each not an appraisal, and none carries the dated, tested sales a board expects. For how a decline in value is defined, see decline in value (Prop 8) in plain words, or browse every article on property tax appeals on the county line.
Next step
If you are preparing a review or an appeal in either county, read how the property tax appeal appraisal is scoped, then send the assessment notice and parcel number, or call (909) 324-6122. Turnaround is typically three to five business days from the inspection, and the fee is set by the scope of the assignment and quoted before work begins.
Sources
- California State Board of Equalization, Publication 30, Residential Property Assessment Appeals: https://www.boe.ca.gov/proptaxes/pdf/pub30.pdf (accessed October 30, 2026)
- California Revenue and Taxation Code section 110 (full cash value): https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC§ionNum=110 (accessed October 30, 2026)
- California Revenue and Taxation Code section 2192 (lien date): https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC§ionNum=2192 (accessed October 30, 2026)
- Los Angeles County Assessment Appeals Board: https://bos.lacounty.gov/services/assessment-appeals/ (accessed October 30, 2026)
- San Bernardino County Clerk of the Board, Assessment Appeals: https://cob.sbcounty.gov/assessment-appeals/ (accessed October 30, 2026)
- San Bernardino County Assessor-Recorder-County Clerk, assessment appeals and informal reviews: https://arc.sbcounty.gov/assessment-appeals/ (accessed October 30, 2026)
Gordon Hall, California Certified Residential Real Estate Appraiser, BREA No. AR003877 (lookup: https://www2.brea.ca.gov/breasearch/faces/party/view.xhtml?id=23601). Reports are prepared in conformity with the Uniform Standards of Professional Appraisal Practice (USPAP). Nothing here is legal or tax advice; admissibility is always the court's decision.
Frequently asked questions
Does an assessment appeals board have to accept an appraisal?
No. The board weighs an appraisal as evidence beside the Assessor's evidence and decides the value itself. The State Board of Equalization's residential appeals guide says a formal appraisal is generally allowed if the board deems it reliable, and the San Bernardino County Clerk of the Board notes that a value may be decreased, increased or left as it is after the evidence is considered.
What date does a property tax appeal appraisal value the house as of?
For a decline-in-value appeal, the January 1 lien date of the year under appeal, set by California Revenue and Taxation Code section 2192. Other appeal types, such as a change in ownership or completed new construction, use the date of that event, as the State Board of Equalization's residential appeals guide explains.
Can comparable sales from after January 1 be used in a tax appeal appraisal?
Only within limits. The State Board of Equalization's residential appeals guide states that comparable sales dated more than 90 days after the valuation date cannot be admitted, and that sales closer to the valuation date are usually viewed as more reliable. An appeal appraisal applies that timing test before choosing its sales.
Is the county's assessed value an appraisal?
No. The assessed value is the value the county Assessor enrolled for tax purposes under California's assessment rules. An appraisal is an independent opinion of market value as of a stated date, developed by a licensed appraiser under the Uniform Standards of Professional Appraisal Practice.
Will the appraiser attend the appeals board hearing?
Only if that is agreed in the scope of work before work begins. A board may ask the person who prepared a report to be present to answer questions. An appraiser who appears explains the report as an independent witness and does not represent the owner.
