Assessor's Division


Clerk's Division  |  Assessor's Division  |  Recorder's Division  |  Elections Division


The Assessor is responsible for determining the assessed value of all taxable property located in San Mateo County. With approximately 236,000 assessments each year, the Assessor's Division creates the official record of taxable property (local assessment roll), shares it with the County Controller and Tax Collector, and makes it publicly available. The local assessment roll is determined by identifying, mapping, inspecting, and calculating the assessed value for all real (land and structures) and business properties. Typically, property tax is 1% of the assessed value, plus an amount to amortize voter-approved bonds, and any fees for special assessments or charges such as mosquito abatement or sewer fees.


The Assessor's Division assesses over 217,000 units on the secured roll and 20,000 units on the unsecured roll. In addition, the Office processes approximately 50,000 transfer documents, 24,000 building permits, 143,000 exemptions, and 10,000 business property statements annually.


San Mateo County claims within its boundaries a wealth of land, buildings, and taxable property with an assessed value of more than $100 billion. The property tax revenues generated from these assets are vital to maintaining local government operations and public services.


For more information, please read 2016-2017 Assessor's Annual Report.


  • Administration
  • Assessed Owners
  • Assessment Appeal Filing
  • Boats, Planes
  • Business Property Information
  • Change in Ownership Information
  • Exemptions
  • Leased Equipment
  • Maps, Property Boundaries
  • Property Characteristics
  • Supplemental Assessments
  • Valuation Information

Special Features

Special Features


Free seminar - How to Prepare and File the 2010 Business Property Statements (Form 571-L)


Assessor Parcel Maps now available online


WARNING! Property Owners - Don't Get Ripped Off!


San Mateo County offers homeowners the ability to fill out an online Decline in Value form. The form takes about 2-3 minutes to complete." (in English, Spanish and Chinese)


Special Features

2012-13 Assessor's Facts & Figures


Number of Parcels & Accounts: 235,979
Total Value of the Combined Roll: $147,256,091,428
Number of building permits processed: 10,850
Number of deeds reviewed & processed for change in ownership transfers: 35,217
Number of Personal Property Assessments Processed: Total 17,268 (which includes 13,799 business accounts, 3,109 boat accounts and 360 aircraft accounts)
[ More Assessor's Facts & Figures]


The Assessor's Division is located at 555 County Center, 1st Floor, Redwood City.


Office hours are Monday through Friday, 8:00 a.m. to 5:00 p.m.



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