Property tax in San Mateo County, California
In San Mateo County, the property tax bill comes from the San Mateo County Treasurer-Tax Collector. The 2026-2027 bill is paid in 2 installments, and the next one is due November 1, 2026. You can look up and pay the bill on the county's own payment page. Taken from San Mateo County's own pages, checked September 23, 2026.
The median property tax bill in San Mateo County, California is $9,519 a year, which is about 0.61% of the county's median home value of $1,559,600. That effective rate is lower than the typical California county (0.7%) and lower than the national median (0.81%). These are American Community Survey 5-year estimates (2024); your own bill depends on your home's assessed value and any exemptions.
Who sends the property tax bill in San Mateo County, and how do you pay it?
The bill comes from the San Mateo County Treasurer-Tax Collector. The value it is based on is set by a separate office, the San Mateo County Assessor-County Clerk-Recorder and Elections, Assessor's Division, which is who to ask if the value looks wrong. For how to look up and pay the bill, go to the county's own payment information.
The Assessor sets the value and the Treasurer-Tax Collector sends the bill and takes the payment; they are separate offices. Secured bills are mailed in October, by November 1. Paying online by eCheck is free; credit cards and PayPal carry a 2.35% fee. Mailed payments for the annual secured bill go to San Mateo County Tax Collector, P.O. Box 45878, San Francisco, CA 94145-0878; supplemental and escape bills go to 555 County Center, 1st Floor, Redwood City. Special charges from cities and local districts, such as sewer fees and school parcel taxes, appear on the same county bill; several school districts offer parcel tax exemptions for seniors, and you apply to the district, not the county. The county also offers an optional monthly payment plan. Since December 24, 2025 the Postal Service may postmark mail a day or more after it is dropped off, so the county suggests asking for a manual postmark at a post office counter near a deadline.
When are property taxes due in San Mateo County?
For the 2026-2027 bill, San Mateo County splits the bill into 2 payments, the first due November 1, 2026 and the last February 1, 2027. A first installment not paid by December 10, 2026 gets a 10% penalty. A second installment not paid by April 12, 2027 gets a 10% penalty plus a $40 cost. Taxes still unpaid after June 30 put the property into tax default, which adds a $35 redemption fee and a penalty of 1.5% a month; property left unpaid for five years may be sold to cover the taxes.
| Payment | Due | Note |
|---|---|---|
| First installment | November 1, 2026 | The county lists November 1 as the due date, but no penalty applies until after 5 p.m. on December 10, 2026 (a Thursday), the last day to pay without penalty. Online payments are accepted until 11:59 p.m. Pacific time that day, and a mailed payment counts only if it carries a U.S. Postal Service postmark on or before that day; a private postage meter date does not count. State law sets these dates for every California county. |
| Second installment | February 1, 2027 | The county lists February 1, 2027 as the due date. The last day to pay without penalty is normally April 10, but April 10, 2027 is a Saturday, and the county and state law move the deadline to 5 p.m. on the next business day, Monday, April 12, 2027. The same online and postmark rules apply. |
From San Mateo County's published schedule, checked September 23, 2026. If a date falls on a weekend or holiday, the county's own rules on the next business day apply.
Estimate the property tax on a home in San Mateo County
Enter a home's market value for a ballpark at San Mateo County's average effective rate of 0.61% (Census). The real bill depends on the home's assessed value, the millage where it sits and any exemptions.
Estimated property tax: $9,514 / year
Property tax in San Mateo County at a glance
| Measure | Value |
|---|---|
| Median annual property tax | $9,519 |
| Median home value | $1,559,600 |
| Effective tax rate | 0.61% |
| Typical California county rate | 0.7% |
| National median county rate | 0.81% |
Effective rate = median real estate taxes paid divided by median home value. Source: U.S. Census Bureau, American Community Survey 5-year estimates.
How does San Mateo County compare in California?
Among California's 58 counties, San Mateo County has the 57th highest effective property-tax rate: 56 rank higher and 1 rank lower. That places it among the least taxed counties in the state. Nationally, it ranks 2210th of 3135 US counties by effective rate. See every California county ranked.
How much do homeowners in San Mateo County actually pay?
The median is only the middle bill. Across San Mateo County's 154,607 owner-occupied homes, 86.1% pay $3,000 or more a year in property tax, 91.4% pay at least $2,000, and 1.5% pay under $800. Another 2.5% report paying no property tax at all, which usually means an exemption covers the whole bill.
| Annual bill | Homes | Share |
|---|---|---|
| Under $800 | 2,337 | 1.5% |
| $800 to $1,499 | 2,761 | 1.8% |
| $1,500 to $1,999 | 4,396 | 2.8% |
| $2,000 to $2,999 | 8,259 | 5.3% |
| $3,000 or more | 133,042 | 86.1% |
| No property tax paid | 3,812 | 2.5% |
Owners with a mortgage pay a median of $10,000+ and owners without one pay $6,502. At least one of those medians hits the Census cap, so the gap between them cannot be measured here. Census table B25103.
How does the San Mateo County property tax bill compare with local incomes?
The median property tax bill of $9,519 is about 4.8% of the median income of San Mateo County homeowner households, $197,950 a year. That compares two middles, so a retiree in a long-held home can pay a far larger share. 58.5% of San Mateo County's occupied homes are lived in by their owners; renters pay property tax too, just folded into rent.
Have property taxes gone up in San Mateo County?
Yes. The median bill went from $6,819 in 2015-2019 to $9,519 in 2020-2024, a 39.6% rise. Over the same span the median home value moved 43.2%, from $1,089,400 to $1,559,600.
Two Census ACS 5-year periods with no survey years in common, in each period's own dollars. A change counts only if it exceeds the combined 90% margin of error.
Property tax in counties next to San Mateo County
San Mateo County borders 4 counties.
| County | Effective rate | Median bill | Median home value |
|---|---|---|---|
| Alameda County, CA | 0.78% | $8,474 | $1,090,100 |
| San Francisco County, CA | 0.71% | $9,862 | $1,394,500 |
| Santa Clara County, CA | at least 0.67% | $10,000+ | $1,490,600 |
| Santa Cruz County, CA | 0.64% | $6,538 | $1,027,500 |
| San Mateo County, CA (this county) | 0.61% | $9,519 | $1,559,600 |
How is a home assessed in San Mateo County?
California sets the assessment rules and San Mateo County applies them. How California assesses and reappraises homes.
Is there a homestead exemption in San Mateo County?
Yes. California's Homeowners' Exemption takes $7,000 off the assessed value of an owner-occupied home. File form BOE-266 with the county assessor by February 15 for the full exemption. That is the California rule, and it applies in San Mateo County. California's exemptions and relief programs in full.
San Mateo County does not add relief programs of its own beyond the California ones (checked September 23, 2026).
How to appeal your San Mateo County property assessment
In San Mateo County you appeal to the San Mateo County Assessment Appeals Board (filed with the Clerk of the Board of Supervisors). The deadline: For the regular annual assessment, file between July 2 and November 30; for 2026 the deadline is Monday, November 30, 2026. An appeal of a supplemental assessment, escape assessment or roll correction is due within 60 days of the mailing date printed on the notice or its postmark date, whichever is later. Each application covers one parcel and one roll year and carries a $30 nonrefundable filing fee. The county asks owners to talk to the Assessor first; the Assessor's free decline-in-value review takes requests until October 31, 2026, and if you have no answer by November 10, 2026 the county recommends filing an appeal anyway to protect your rights. How to file. Checked September 23, 2026 against the official appeal rules.
How California's appeal process works, including the next level if the first one turns you down.
California rules from primary state sources, reviewed September 7, 2026; sources on the California page.
Work out your own numbers
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How much house can I afford?
Your income, debts and down payment against the 28/36 rule lenders actually use, with San Mateo County's tax rate to hand.
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Mortgage calculator
Monthly payment with principal, interest, tax and insurance, plus what an extra payment saves you.
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California income tax
Brackets, standard deduction and what California actually taxes.
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Sales tax in San Mateo County
The other local tax: combined state and local rate for this county.
Sources
- Median real estate taxes paid and median home value for San Mateo County, California: U.S. Census Bureau, American Community Survey 5-year estimates (2020-2024), tables B25103, B25077, B25102, B25119 and B25003; the five-year comparison uses the 2015-2019 estimates. Neighboring counties: Census county adjacency file.