Santa Clara County Property Tax Appeal: Deadline and Fee

Santa Clara County homeowners appeal an assessment by filing an Application for Changed Assessment with the Clerk of the Board, which serves the county's Assessment Appeals Board, during a regular filing period that opens July 2 and, for 2026, closed September 15. The county charges $290 per application for residential, vacant, and agricultural property, effective June 1, 2026, which is the highest routine residential filing fee among the large California counties. That fee changes the math: a Santa Clara appeal is worth filing when the gap between your assessed value and the market is clear, and worth skipping when it is marginal.

Who decides your appeal

The Assessment Appeals Board is independent of the Assessor. The Clerk of the Board of Supervisors accepts applications, collects the fee, and schedules hearings. The complete homeowner's guide explains what an appeal argues and what evidence wins; this page covers what is specific to Santa Clara County.

The deadline: September 15

California's regular filing period opens July 2 in every county and closes September 15 or November 30, depending on whether the assessor mails value notices to all secured-roll owners by August 1 (Cal. Rev. & Tax. Code section 1603(b)). Santa Clara's Assessor mails on time, so the county is on the September 15 list in the Board of Equalization's Letter To Assessors 2026/023. That is ten and a half weeks earlier than Los Angeles, Orange, or San Diego, and it catches owners who assume the November date applies statewide. The California deadline guide has all 58 counties.

If the closing date falls on a weekend or holiday, an application postmarked the next business day is timely (section 1603(b)(4)). A supplemental or escape assessment, such as the one after a purchase, has its own 60-day window from its notice (Publication 30); see appealing after buying a house.

The $290 fee, and what it means for a homeowner

From June 1, 2026, the Clerk of the Board charges $290 per application for residential, vacant, and agricultural property, and $675 for commercial, business, and multifamily property of five or more units. The county publishes a waiver for owners receiving public assistance. The fee is not refunded if you lose.

For comparison, Los Angeles charges $46, San Francisco $120, and Orange and San Diego nothing; the cost guide has the verified table. A $290 fee does not make an appeal a bad idea, but it does raise the bar. Run the five-minute calculation in is an appeal worth it?: multiply the gap between your assessed value and what similar homes sold for by your effective tax rate, and compare the first-year saving with the fee. On a typical Santa Clara home, a gap of a few percent covers the fee several times over in one year; a gap of one percent may not.

Do the free step first

The Board of Equalization's Publication 30 tells homeowners to "first meet informally with the assessor to discuss the assessment." In Santa Clara that is a decline-in-value review request to the Assessor. Under Rev. & Tax. Code section 51(a)(2), the Assessor must enroll the lower of your factored Proposition 13 base year value and your home's market value on January 1. The Assessor reviews many properties for decline in value each year without being asked, but a request with comparable sales attached gets a specific answer. The Prop 8 guide explains the review.

The request does not extend the September 15 deadline. If the Assessor has not agreed by early September and the gap justifies the fee, file the formal application and keep talking.

How to file

The form is the state's BOE-305-AH, Application for Changed Assessment, filed with the Clerk of the Board with the fee or the waiver. It asks for the parcel number, the roll value, your opinion of value, and the basis. Under Cal. Rev. & Tax. Code section 1604(c), if the board does not hear and decide the application within two years of a timely filing, your opinion of value becomes the assessed value unless you agreed in writing to an extension. Write a number you can support with sales, not a wish. What to write on the form covers each field.

Evidence that works

Closed sales of similar homes in your neighborhood near January 1, adjusted for size, age, and condition. For a decline-in-value case, Publication 30 says comparable sales should be no later than 90 days after the lien date. How to find comparable sales shows how. Check the Assessor's record of your home first; a wrong square footage is the cheapest argument to win. For an owner-occupied home, Rev. & Tax. Code section 167(a) gives you a rebuttable presumption in your favor once you have supplied the information the law requires.

Keep paying

Publication 30: "Filing an application does not excuse the payment of taxes." Pay both installments; a win is refunded for the appealed year.

Common questions

I missed September 15, 2026. What now?

The regular appeal for 2026 is closed. You can still request an informal decline-in-value review from the Assessor, watch for any supplemental or escape notice with its own 60-day window, and prepare for the window that reopens July 2, 2027.

Is the $290 refundable if I win?

No. The county's fee is non-refundable. The only way around it is the public-assistance waiver, which few homeowners qualify for.

Can someone file and appear for me?

Yes. An agent may represent you with written authorization on the application (Publication 30). Drop Property Tax reviews the record and the sales for free and charges nothing unless the appeal wins, which matters more in a $290 county than anywhere else; start with a free review.

Why is Santa Clara's fee so much higher than Los Angeles County's?

Each California county sets its own fee for the Clerk of the Board's costs. Santa Clara raised its fee to $290 for residential property from June 1, 2026. Nothing in state law fixes the amount.