County filing guide
How to appeal your property tax in Santa Clara County
Regular decline-in-value appeals. Supplemental and escape assessments have different deadlines.
Filing options
A filing-fee waiver may be available. Check with the county to see whether you qualify.
Filing instructions
Informal review
The informal review window for 2026-27 has closed (it ran through August 8, 2026). Check the county's page for next cycle's review window. These instructions remain available as a reference.
Open the Assessor’s decline-in-value page and click Start New Filing Request / Modify Existing Request. If the portal is not working, use the contact published on the county’s request page: (408) 299-5300 or [email protected].
The Assessor's decline-in-value page with the Start New Filing Request button highlighted. Type your APN and PIN into the input box.
The request form showing the APN and PIN input fields. Submit the request and keep the confirmation.
The formal appeal window for 2026-27 has closed. The deadline was September 15, 2026. These instructions remain available as a reference.
Formal appeal online
Open the Santa Clara assessment appeals portal.
Click Login / Sign up.
The Clerk of the Board assessment appeals portal with the Log in or Sign up button highlighted. Click File an appeal.
The portal listing with the File an appeal action highlighted. Select Residential to proceed.
The application type chooser with the Residential option highlighted. Fill out the necessary fields of the application.
The application form fields to fill out. Continue filling out the form.
The application form's continuation screen. Follow the application guide to finish the application.
After you file
Informal review
Keep your request confirmation and any correspondence from the Assessor. Check the formal appeal deadline above when considering a separate appeal.
Formal appeal
Keep a copy of your application and filing confirmation. Watch for notices from the Clerk of the Board and follow the county’s instructions for any hearing.
Open my appeal plans →Contacts & sources
Clerk of the Board
Runs the formal appeal
408-299-5088 · appeals page ↗
70 West Hedding Street, East Wing, 10th Floor, San Jose, CA 95110
This guide covers the regular decline-in-value appeal; supplemental or escape assessment notices follow different deadlines. Every date and fee here was checked against official sources, listed below with the date checked. If the county's page ever differs from this guide, follow the county's page.
Sources
Informal sources
Informal review
- https://asr.santaclaracounty.gov/online-services/decline-in-value/prop-8-important-point · “The filing period starts June 30 and ends on Aug 8” (checked July 11, 2026)
- https://asr.santaclaracounty.gov/online-services/decline-in-value/decline-in-value-request · “Remember, the informal review filing period begins June 30th and ends August 1st.” (checked July 20, 2026)
- https://cob.santaclaracounty.gov/appeal-your-property-taxes · “you may also request a free informal assessment review with the Office of the Assessor” (checked July 11, 2026)
- https://www.sccassessor.org/RP/prop8/declineinvalue.asp?drupal=true · “Requests for review must have been submitted to the Assessor’s Office by August 8, 2026” (checked September 7, 2026)
Formal sources
Formal appeal window
- https://www.boe.ca.gov/proptaxes/pdf/lta26023.pdf · “The regular appeals filing period in each county will begin on July 2, 2026, and will end on September 15, 2026, for those counties where the Assessor mails assessment notices to all taxpayers with property on the secured roll by August 1, 2026. For counties where assessment notices are not mailed by August 1, 2026, the filing period is extended to November 30, 2026.” (checked July 10, 2026)
Filing fee
- https://cob.santaclaracounty.gov/appeal-your-property-taxes · “Beginning June 1, 2026, the Office of the Clerk of the Board will charge a nonrefundable administrative processing fee at the time of filing an assessment appeal in the amount of: $290 per parcel/application for residential, vacant land, and agricultural properties $675 per parcel or account/application for commercial, business, and multifamily properties with 5 or more units” (checked July 11, 2026)
Value notice
- https://asr.santaclaracounty.gov/online-services/decline-in-value/prop-8-important-point · “The Notification of Assessed Value is mailed last week in June” (checked July 11, 2026)
Filing address
- https://cob.santaclaracounty.gov/appeal-your-property-taxes · “Assessment Appeals Division 70 West Hedding Street East Wing, 10th Floor San Jose, CA 95110” (checked July 11, 2026)
Filing channels
- https://sccgovaa.custhelp.com/ · “Before you begin filing your application online, you should have available the assessment notice you recently received. Completing the online application will take approximately 15 minutes.” (checked July 11, 2026)
Fee waiver
- https://cob.santaclaracounty.gov/appeal-your-property-taxes · “Assessment appeal processing fees may be waived for applicants who receive public assistance.” (checked July 11, 2026)
Common questions about appealing in Santa Clara County
When is the deadline to appeal in Santa Clara County?
The 2026-27 filing period for a formal appeal in Santa Clara County ran from July 2 to September 15, 2026, so it has closed for this tax year.
The Assessor's informal review window ran from June 30 to August 8, 2026.
What does it cost to file an appeal in Santa Clara County?
The county filing fee for a formal appeal is $290 for an owner-occupied home.
There is no fee for the Assessor's informal review.
A filing-fee waiver may be available. Check with the county to see whether you qualify.
Informal review or formal appeal: which one first?
Santa Clara County offers both: an informal review with the Assessor, and a formal appeal filed with the Clerk of the Board (due September 15, 2026).
The state's own guidance says to talk to the Assessor's office first: if their staff finds an error, they can lower the roll directly and you may never need to file. Missing an informal review costs you nothing; missing the formal deadline costs you the year.
Which form do I file, and where?
The formal appeal uses the state's application form, BOE-305-AH ↗.
Santa Clara County accepts the formal appeal online. File online through the county's appeals portal ↗.
The Clerk of the Board's address is 70 West Hedding Street, East Wing, 10th Floor, San Jose, CA 95110.
Check the Clerk of the Board's appeals page ↗ or call 408-299-5088 before you file.
How long does an appeal take?
You get written notice at least 45 days ahead, hearings are open to the public (you can watch one first), and boards are expected to decide within two years of filing. You can still settle at any point before your date.
Do homeowners actually get their assessments lowered?
Homeowners in Santa Clara County whose assessments were reduced for 2025-26 saved about $1,855 in property taxes on average.