How to appeal a San Mateo County, CA property assessment
✓ Verified — Last verified October 24, 2026
Filing details published for San Mateo County. Match the notice and assessment cycle to the official instructions.
Official appeal instructionsNot tax or legal advice; confirm with your county.
Filing timing
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Where to file
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Official offices
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San Mateo County Assessor Division
Sources for these instructions
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Read the source quotations (16)
https://smcacre.gov/assessor/property-tax-relief
The AAB’s filing deadline schedule for 2026 assessment appeals for regular assessment is from July 2, 2026 through November 30, 2026.
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https://www.smcgov.org/ceo/preparing-your-appeals-application
San Mateo County Assessment Appeals Board 500 County Center, 5th Floor, BOS 104 Redwood City, CA 94063
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https://www.boe.ca.gov/proptaxes/calendar.htm
§ 2605 Rev. & Tax. Code November 1 Property owners First installment of real property taxes and all taxes on personal property on the secured roll are due and payable.
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https://www.boe.ca.gov/proptaxes/calendar.htm
§§ 2617 and 2704 Rev. & Tax. Code December 10 Property owners First installment of taxes on the secured roll, if unpaid, is delinquent at 5:00 p.m. or close of business day, whichever is later.
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https://www.boe.ca.gov/proptaxes/calendar.htm
If the specified date falls on Saturday, Sunday, or a legal holiday, the action may be done on the next business day. (Government Code §§ 6706, 6707)
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https://www.boe.ca.gov/proptaxes/calendar.htm
§ 2606 Rev. & Tax. Code February 1 Property owners Second installment real property taxes due and payable.
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https://www.boe.ca.gov/proptaxes/calendar.htm
§§ 2617 and 2704 Rev. & Tax. Code December 10 Property owners First installment of taxes on the secured roll, if unpaid, is delinquent at 5:00 p.m. or close of business day, whichever is later.
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https://www.smcgov.org/tax
A 10% penalty is added the next day A 10% penalty plus $40.00 cost is added the next day A redemption fee of $35.00 and a monthly penalty of 1.5% will be added to Secured defaulted parcels If a delinquent date falls on a weekend or holiday, the delinquent date is the next business day.
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https://www.smcgov.org/ceo/news/county-controller-publishes-property-tax-highlights-fy-2024-25
More recently, they grew by 4.9 percent for FY 2025-26, and by 4.3 percent for FY 2026-27 based on assessed values as of the lien date of January 1, 2026.
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https://smcacre.gov/assessor/location/assessor-division
555 County Center 3rd Floor Redwood City, CA 94063-1665
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Continue with your property
Common questions
Where do I file a San Mateo County assessment appeal?
San Mateo County Assessment Appeals Board, 500 County Center, 5th Floor, BOS 104, Redwood City, CA 94063
Updated , from cited verification dates. Individual sources may have earlier checks.