San Mateo County Assessor Office

Find San Mateo County California assessor, assessment, auditor's, and appraiser's offices, revenue commissions, GIS, and tax equalization departments. Assessors provide information on property and land tax assessment, property listings, values, valuations, property search, and records.


San Mateo County Assessor's Office 555 County Center Redwood CA 94063 650-363-4500


About the San Mateo County Assessor Office

Assessor Offices in San Mateo County, CA are responsible for assessing the values of all taxable property within their jurisdictions. Assessors appraise values of all land and commercial property (real property), and business' fixed asset (personal property). The office determines property tax values, tax rates, maintains and updates the local tax assessment rolls.

Property owners may contact the Department of Assessment for questions about:
  • San Mateo County property tax appeals and challenges
  • Property tax assessments and reassessments
  • San Mateo County GIS maps, plat maps, and property boundaries
  • Delinquent property taxes
  • San Mateo County, CA property tax payments and due dates
  • Assessment rolls and property tax rates
San Mateo County Property Records

San Mateo County Assessors keep property records for all real property within their jurisdictions. The Office maintains records which include geographic area, land size, building size and type as well as GIS maps, plat maps, and property boundaries. The Office also maintains public records available for search, including historical assessments of real and personal property, property deeds and bills of sale.

Property Assessments

Tax assessors adjust San Mateo County, California real property valuations and real estate tax rates by tracking comparable real estate sales and market valuations. Assessors track zoning requirements, construction permits, renovations, demolitions, working with Building Departments and Inspectors to reflect accurate changes to the property list.

Property Re-Assessments

Real property assessments are reassessed at intervals set by the local government. During reassessments San Mateo County Assessors update real property values based on changes in market conditions, additions and removals to the property list.

San Mateo County, California Personal Property Assessments

Businesses in San Mateo County are responsible for self-reporting personal property to the office of the Tax Assessor.