Sonoma County Property Tax
1.139% average rate in fiscal year 2024-25 · The 15th-highest of California's 58 counties
The average property tax rate in Sonoma County is 1.139% of assessed value (fiscal year 2024-25): the 1% Prop 13 levy every California property pays, plus 0.139% in voter-approved debt. On a home assessed at $750,000 with the homeowners' exemption, that is about $8,463 a year. The rate is below the 1.152% average across all 58 counties.
Sonoma County Property Tax Calculator
Estimated yearly property tax
Property tax on typical home values in Sonoma County
| Assessed value | Primary residence (with exemption) | Rental or second home | Each installment (residence) |
|---|---|---|---|
| $500,000 | $5,615 | $5,695 | $2,808 |
| $750,000 | $8,463 | $8,543 | $4,231 |
| $1,000,000 | $11,310 | $11,390 | $5,655 |
At 1.139%, the $7,000 homeowners' exemption saves $80 a year. Prop 13 lets a home's assessed value rise by no more than 2% a year until it sells or is newly built on, so owners who bought years ago usually pay on far less than market value.
How Sonoma County's rate compares
Sonoma County's 1.139% average is the 15th-highest of California's 58 counties and below the 1.152% average for the state as a whole. Every county starts at the same 1% levy; the difference is voter-approved bonds for schools, water and other local projects, which add 0.139% here.
| Fiscal year | Average rate in Sonoma County |
|---|---|
| 2024-25 | 1.139% |
| 2023-24 | 1.140% |
| 2022-23 | 1.133% |
| 2021-22 | 1.140% |
| 2020-21 | 1.169% |
| 2019-20 | 1.158% |
| 2018-19 | 1.163% |
| 2017-18 | 1.159% |
| 2016-17 | 1.151% |
| 2015-16 | 1.134% |
| 2014-15 | 1.126% |
Over the 11 years shown, the average ranged from 1.126% to 1.169%, up from 1.126% in 2014-15. The rate moves as old bonds are paid off and new ones are approved.
Sonoma County vs. neighboring counties
Sonoma County borders 6 counties. 3 of them have a higher average rate and 3 a lower one. On a $750,000 home with the homeowners' exemption, the yearly difference looks like this:
| County | Average rate (2024-25) | Tax on $750,000 | vs. Sonoma County |
|---|---|---|---|
| Sonoma County | 1.139% | $8,463 | — |
| Solano County | 1.179% | $8,760 | +$297 |
| Mendocino County | 1.152% | $8,559 | +$96 |
| Contra Costa County | 1.151% | $8,552 | +$89 |
| Marin County | 1.133% | $8,418 | −$45 |
| Lake County | 1.115% | $8,284 | −$179 |
| Napa County | 1.104% | $8,203 | −$260 |
These are county averages. Two parcels a mile apart can differ by more than this if they sit in different school or water bond districts, so check the tax rate area on a listing's last bill.
Where Sonoma County's property tax goes
In 2024-25, property owners in Sonoma County were levied $1.4 billion. For every $100:
| Recipient | Of every $100 | Total levied |
|---|---|---|
| Schools and community colleges | $61.67 | $860 million |
| County government | $19.62 | $273 million |
| Special districts (water, fire, parks, transit and others) | $13.49 | $188 million |
| Cities | $5.22 | $72.8 million |
Sonoma County property tax payment dates
| 2026-27 bill | Due | Late after 5 p.m. on | Penalty if late |
|---|---|---|---|
| First installment | Nov 1, 2026 | Dec 10, 2026 | 10% |
| Second installment | Feb 1, 2027 | Apr 12, 2027 | 10% plus a cost charge |
State law sets these dates for every county. A purchase or new construction also brings a supplemental bill from the Sonoma County Tax Collector, which the calculator above estimates. How the bill is calculated →
Sonoma County Assessor and Tax Collector
| Office | What it handles | Phone |
|---|---|---|
| Sonoma County Assessor | Assessed values, the homeowners' and other exemptions, Prop 19 base-year transfers, decline-in-value (Prop 8) reviews | 707-565-1888 |
| Sonoma County Tax Collector | Tax bills, payments, supplemental bills, penalties and payment plans | 707-565-2281 |
On the 2025-26 roll, Sonoma County property was assessed at $129.4 billion after exemptions, up 5.5% from 2024-25.
Appealing your assessed value in Sonoma County
In 2026, Sonoma County's regular appeal filing period runs from July 2, 2026 to November 30, 2026. That is the extended November 30 deadline, which applies because the Sonoma County Assessor does not mail a value notice to every property owner by August 1. The window is open now.
Before filing, you can ask the Sonoma County Assessor for a free decline-in-value (Prop 8) review if the property was worth less than its assessed value on January 1. A formal appeal goes to the county's assessment appeals board on form BOE-305-AH, and the bill must still be paid while it is pending. The BOE's residential appeals guide walks through the hearing.
Exemptions you can claim in Sonoma County
The homeowners' exemption takes $7,000 off a primary residence's assessed value, worth $80 a year at Sonoma County's average rate; 70,295 homes here claim it (check if you qualify). The county also counts 1,126 disabled veterans' exemptions. Charities, hospitals and religious groups can claim the welfare exemption.
Low-value exemption: Sonoma County is one of the counties that skip property worth so little that the tax would cost more to collect than it raises (R&TC 155.20); $11,560,000 of value was exempt this way on the 2025-26 roll. The board of supervisors sets the threshold, up to $10,000 of value.
Not sure which applies? The Property Tax Exemption Finder sorts it out in three questions.
Other local costs in Sonoma County
Transfer tax when you sell: the county documentary transfer tax is $0.55 per $500 of value ($1.10 per $1,000), or $825 on a $750,000 sale. Some charter cities add their own transfer tax on top (the calculator covers Petaluma and Santa Rosa). Calculate it.
Sales tax by city: Santa Rosa.
Local minimum wage: Petaluma, Santa Rosa, Sonoma.
Frequently Asked Questions
What is the property tax rate in Sonoma County?
The average total property tax rate in Sonoma County was 1.139% of assessed value in fiscal year 2024-25, according to the State Board of Equalization: the 1% Prop 13 general levy plus 0.139% in voter-approved debt. Your parcel's exact rate depends on its tax rate area and is printed on the bill.
How much is property tax on a $750,000 home in Sonoma County?
About $8,463 a year at the county's average rate if the home is assessed at $750,000 and you claim the $7,000 homeowners' exemption ($8,543 without it). Parcel taxes, Mello-Roos and other direct charges on the bill are extra.
How do I look up my assessed value or pay my bill in Sonoma County?
The Sonoma County Assessor sets assessed values and handles exemptions (707-565-1888). The Tax Collector sends the bills and takes payments (707-565-2281). Both offices are linked on this page.
What is the deadline to appeal my assessed value in Sonoma County?
In 2026, Sonoma County's regular appeal filing period runs from July 2, 2026 to November 30, 2026. That is the extended November 30 deadline, which applies because the Sonoma County Assessor does not mail a value notice to every property owner by August 1. The window is open now. An appeal of a supplemental or escape assessment has its own deadline, generally 60 days from the notice.
Does Sonoma County exempt low-value property?
Yes. The Board of Equalization's figures show Sonoma County exempts some low-value property under Revenue and Taxation Code 155.20, which lets a county skip property whose tax would cost more to collect than it brings in ($11,560,000 of value was exempt on the 2025-26 roll). The limit is set by the board of supervisors, up to $10,000 of value; ask the assessor for the current threshold.
Sources
- BOE Property Tax Allocations (Tables 14 and 15): average rate and where the levy goes
- BOE Net Assessed Values by County (Table 10), Gross Assessed Values and Homeowners' Exemptions (Table 9) and Property Tax Exemptions (Table 8)
- BOE County Contacts: assessor and tax collector offices
- BOE Letter to Assessors 2026/023 (June 2, 2026): each county's assessment appeal filing deadline; Revenue and Taxation Code 1603 and 1605
- U.S. Census Bureau county adjacency file: neighboring counties
- California Revenue and Taxation Code sections 2192, 2605, 2606, 2607, 2617, 2618, 2619 and 2621 (lien date, payment deadlines and the delinquency cost charge), 75.41 (supplemental bills) and 155.20 (low-value exemption), on leginfo.legislature.ca.gov
Educational estimate only. The rate shown is the county's average across all tax rate areas for fiscal year 2024-25; a specific parcel's rate can be higher or lower, and direct charges vary by property. Your tax bill from the Sonoma County Tax Collector is the final word.