Property tax in Sonoma County, California
In Sonoma County, the property tax bill comes from the Sonoma County Auditor-Controller-Treasurer-Tax Collector. The 2026-27 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 Sonoma County's own pages, checked September 23, 2026.
The median property tax bill in Sonoma County, California is $5,695 a year, which is about 0.7% of the county's median home value of $815,500. That effective rate is about the same as 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 Sonoma County, and how do you pay it?
The bill comes from the Sonoma County Auditor-Controller-Treasurer-Tax Collector. The value it is based on is set by a separate office, the Sonoma County Clerk-Recorder-Assessor, Assessor's Office, 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 Auditor-Controller-Treasurer-Tax Collector sends the bill and takes the payment; they are separate offices. Annual bills are mailed in the fall; ask for a copy if yours has not arrived by November 10. Paying online by eCheck is free; credit and debit card payments carry a 2.34% fee. A monthly payment option is offered through an outside vendor for bills of $250 or more, with a lower 1.99% card fee. Some school districts exempt owners 65 and older or on disability benefits from their parcel taxes; you apply to the school district, not the county.
When are property taxes due in Sonoma County?
For the 2026-27 bill, Sonoma 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 $20 administrative charge. Taxes still unpaid at 5 p.m. on June 30 go into tax default, which adds a $15 redemption fee and penalties of 1.5% a month on the unpaid tax, added at the end of each month starting in July.
| 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. A mailed payment must be postmarked on or before that day; because of Postal Service changes, the county suggests asking for a hand postmark or a certificate of mailing, or mailing well ahead. State law sets these dates for every California county. |
| Second installment | February 1, 2027 | The county lists February 1 as the due date. The last day to pay without penalty is normally April 10, but April 10, 2027 is a Saturday, and both state law and the county move the deadline to 5 p.m. on the next business day, Monday, April 12, 2027. The same postmark advice applies. |
From Sonoma 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 Sonoma County
Enter a home's market value for a ballpark at Sonoma County's average effective rate of 0.7% (Census). The real bill depends on the home's assessed value, the millage where it sits and any exemptions.
Estimated property tax: $5,709 / year
Property tax in Sonoma County at a glance
| Measure | Value |
|---|---|
| Median annual property tax | $5,695 |
| Median home value | $815,500 |
| Effective tax rate | 0.7% |
| 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 Sonoma County compare in California?
Among California's 58 counties, Sonoma County has the 29th highest effective property-tax rate: 28 rank higher and 29 rank lower. That is near the middle for California. Nationally, it ranks 1880th of 3135 US counties by effective rate. See every California county ranked.
How much do homeowners in Sonoma County actually pay?
The median is only the middle bill. Across Sonoma County's 119,598 owner-occupied homes, 75.6% pay $3,000 or more a year in property tax, 83.6% pay at least $2,000, and 4.2% pay under $800. Another 4% report paying no property tax at all, which usually means an exemption covers the whole bill.
| Annual bill | Homes | Share |
|---|---|---|
| Under $800 | 5,062 | 4.2% |
| $800 to $1,499 | 5,944 | 5% |
| $1,500 to $1,999 | 3,674 | 3.1% |
| $2,000 to $2,999 | 9,610 | 8% |
| $3,000 or more | 90,470 | 75.6% |
| No property tax paid | 4,838 | 4% |
Owners with a mortgage pay a median of $6,174 and owners without one pay $4,519. Owners who have paid off a home have usually held it longer, and in states that cap how fast an existing owner's assessment can rise, long-held homes carry lower assessed values. Census table B25103.
How does the Sonoma County property tax bill compare with local incomes?
The median property tax bill of $5,695 is about 4.4% of the median income of Sonoma County homeowner households, $128,478 a year. That compares two middles, so a retiree in a long-held home can pay a far larger share. 62.6% of Sonoma 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 Sonoma County?
Yes. The median bill went from $4,253 in 2015-2019 to $5,695 in 2020-2024, a 33.9% rise. Over the same span the median home value moved 33.8%, from $609,600 to $815,500.
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 Sonoma County
Sonoma County borders 6 counties.
| County | Effective rate | Median bill | Median home value |
|---|---|---|---|
| Contra Costa County, CA | 0.83% | $7,156 | $866,800 |
| Solano County, CA | 0.75% | $4,621 | $617,700 |
| Lake County, CA | 0.73% | $2,369 | $324,300 |
| Sonoma County, CA (this county) | 0.7% | $5,695 | $815,500 |
| Mendocino County, CA | 0.69% | $3,545 | $512,200 |
| Napa County, CA | 0.69% | $5,995 | $869,500 |
| Marin County, CA | at least 0.66% | $10,000+ | $1,507,300 |
How is a home assessed in Sonoma County?
California sets the assessment rules and Sonoma County applies them. How California assesses and reappraises homes.
Is there a homestead exemption in Sonoma 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 Sonoma County. California's exemptions and relief programs in full.
Sonoma County does not add relief programs of its own beyond the California ones (checked September 23, 2026).
How to appeal your Sonoma County property assessment
In Sonoma County you appeal to the Sonoma 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 window runs to Monday, November 30, 2026. An appeal of a supplemental or escape assessment is due within 60 days of the mailing date or postmark date on that notice, whichever is later. The application form the county currently posts lists a $30 nonrefundable processing fee, which can be waived for applicants whose finances would qualify them for a court fee waiver. The Assessor's informal review for the 2026-27 value is closed; its informal review for the January 1, 2027 value runs from December through March 15. 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 Sonoma 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 Sonoma County
The other local tax: combined state and local rate for this county.
Sources
- Median real estate taxes paid and median home value for Sonoma 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.