San Mateo County, CA Property Tax: $9,167/yr (2026)
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The effective property tax rate in San Mateo County is 0.61% of assessed home value. On a home at the county median value of $1,494,500, that works out to about $9,116 per year, or $760 per month. San Mateo County is located in western California, and is home to approximately 745,100 residents.
About San Mateo County
San Mateo County covers approximately 448.6 square miles in California. The county is home to about 745,100 residents living in roughly 285,558 housing units, of which 54.7% are owner-occupied. The median household income is $156,000, and the median home was built in 1966.
San Mateo County borders Alameda County, San Francisco County, Santa Clara County, Santa Cruz County — useful comparisons if you're considering nearby areas with potentially different tax rates.
How Property Taxes Work in California
Property taxes in California are administered at the county level. Each county sets a millage rate applied to the assessed value of real property — the effective rate above accounts for any partial assessments and exemptions already built into the local tax base. Assessed value can differ meaningfully from current market value depending on how often the county reassesses and what fraction of market value it uses.
Most counties in California offer exemptions that reduce the taxable assessed value: homestead exemptions for primary residences, senior exemptions, disability exemptions, and veteran exemptions are common. These reduce your effective rate below the county-wide average shown here. Contact the San Mateo County Assessor's office to learn which exemptions apply to your property and when to file.
San Mateo County vs. Neighboring Counties
| Location | Eff. Rate | Median Home | Annual Tax |
|---|---|---|---|
| San Mateo County, CA | 0.61% | $1,494,500 | $9,116 |
| California state average | 0.71% | — | $10,611* |
| Alameda County | 0.76% | $1,057,400 | $8,061 |
| San Francisco County | 0.68% | $1,380,500 | $9,412 |
| Santa Clara County | 0.71% | $1,382,800 | $9,766 |
| Santa Cruz County | 0.62% | $1,015,200 | $6,305 |
| US national average | 1.10% | $281,900 | $3,101 |
*State average annual tax computed at San Mateo County's median home value of $1,494,500. Source: US Census ACS 2023 5-year estimates.
Frequently Asked Questions
How does San Mateo County's property tax rate compare to the rest of California?
At 0.61%, San Mateo County is lower than the California state average of 0.71%. On a home at the county median of $1,494,500, that means about $9,116 per year — versus $10,611 at the state average rate, a difference of $1,495 per year. Compared to the national average of 1.10%, San Mateo County is below average.
What's a typical annual property tax bill in San Mateo County?
For a home at the county median value of $1,494,500, the annual property tax in San Mateo County is approximately $9,116 — or about $760 per month. For a home worth $2,241,750, expect around $13,675 per year. For a $2,989,000 home, approximately $18,233 per year. Use the calculator above to estimate taxes for any assessed value.
Where do I appeal a San Mateo County property tax assessment?
Property assessment appeals in San Mateo County are handled by the San Mateo County Assessor's office. Most jurisdictions require filing within 30–90 days of receiving your assessment notice — confirm the specific deadline with the assessor's office before submitting, as deadlines and procedures vary by county. A successful appeal can reduce your assessed value and lower your tax bill for the current and future tax years.
What exemptions are available in San Mateo County?
California counties commonly offer homestead exemptions for owner-occupied primary residences, senior citizen exemptions for qualifying homeowners aged 65 and older, exemptions for disabled residents, and veterans' exemptions. Each exemption reduces your assessed taxable value, which in turn reduces your effective tax rate below the county-wide 0.61% shown here. Contact the San Mateo County Assessor's office to confirm which exemptions are available and the application deadlines.
Data sources: US Census Bureau ACS 2023 5-Year Estimates, US Census Gazetteer (2024), County Adjacency File