Sonoma County Property Tax: Rates by City, Bills and Deadlines

Sonoma County property tax rates by city

Every Sonoma County bill starts with the same 1% countywide levy set by Proposition 13. What changes from town to town is the stack of voter-approved bond rates on top of it, and in Sonoma County most of that stack is school debt. The county's Multi-Year Tax Rates report for 2026-27, issued September 15, 2026, gives the full rate for every tax rate area. We took the most common TRA in each city. Your parcel can sit in a different elementary district than its city name suggests, so treat these as examples and check your own bill.

Cloverdale lands at the top of this list because its TRAs add a City of Cloverdale debt service rate of 0.0610% on top of Cloverdale Unified's two bonds. The city of Sonoma sits lowest, at 1.11396%: Sonoma Valley Unified's two bonds and the health care district bond add less than the school stacks elsewhere. Healdsburg fell from 1.1570% in 2025-26 because its 2002 SFID bond no longer appears in the 2026-27 rates. The Redfin column is there so you can see the price levels these rates apply to; it is not the value on anyone's bill.

Tax rate areas and the bond rates behind them

Sonoma County splits its map into tax rate areas, or TRAs, shown as a six-digit code such as 004-001 on your bill. Each TRA is a unique overlap of city, school, college, fire and water boundaries. The Auditor-Controller-Treasurer-Tax Collector (ACTTC) applies the combined rate for your TRA to your assessed value. Its Computing Your Taxes page says the general levy is limited to $1 per $100 of value and that special taxes and district assessments are added by vote.

School bond rates that moved for 2025-26

These changes come from Resolution 25-0415, adopted September 16, 2025. Several moved again for 2026-27: Windsor Unified 2008 to 0.0475%, Cotati-Rohnert Park Unified 2024 to 0.0340%, Santa Rosa Elementary 2022 to 0.0300% and the Junior College 2014 bond to 0.0180%. The resolution lists Sonoma Water's Warm Springs Dam and Russian River Project levy at 0.0070% for both years, and it is still 0.0070% for 2026-27. Two bond series from neighboring counties reach into Sonoma parcels: Shoreline Unified (governed by Marin County) and Calistoga Joint Unified and Napa Valley College (governed by Napa County). Those rates are set by the other county's board.

Finding your own TRA in Sonoma County

Your TRA code is printed on the secured bill next to the parcel number. You can also search the parcel on the county's online tax portal, linked from the How to Pay Your Property Taxes page. Before you buy, ask the title officer for the TRA and the last full-year bill. That bill shows every bond and direct charge, which the rate alone does not.

A worked Sonoma County tax bill under Prop 13

Zillow's typical home value for Sonoma County was $782,980 in September 2026. Here is what a buyer paying that price for a home in the Santa Rosa example area above would owe in the first full year, using the 2026-27 rates.

1. Assessed value set at purchase: $782,980.
2. Less the homeowners' exemption: $782,980 minus $7,000 = $775,980 taxable.
3. 1% Prop 13 levy: $775,980 x 1.0000% = $7,759.80.
4. Voter-approved bonds and Sonoma Water: $775,980 x 0.1315% = $1,020.41.
5. Ad valorem total: $775,980 x 1.1315% = $8,780.21.
6. Add fixed charges and parcel taxes, which are flat amounts per parcel, not percentages.

The same price in the city of Sonoma example area (1.11396%) gives $8,644.11 before fixed charges. In the Cloverdale example area (1.1690%) it gives $9,071.21. The BOE's 2024-25 average rate for the whole county, 1.139%, gives $8,838.41, so the Santa Rosa example sits close to the county's middle.

How the Sonoma bill grows after year one

Prop 13 lets the assessed value rise by no more than 2% a year while you own the home. At the maximum, $782,980 becomes $798,640 in year two and about $864,473 after five years. Bond rates change every year, so the total can move up or down even when the value rises by the full 2%. Zillow shows the county's typical value up 0.8% over the year to September 2026 and below its June 2022 peak of $809,862. If the market value of a home ever falls below its factored Prop 13 value, the assessor can enroll the lower figure under a decline-in-value review.

Sonoma County property tax exemptions

Sonoma County's Clerk-Recorder-Assessor handles exemptions and exclusions. Its Tax Savings page lists the homeowners', veterans' and disabled veterans' exemptions, along with exclusions for solar systems, seismic retrofits and disaster rebuilds. The office notes its staff cannot give legal advice on which forms to file.

Homeowners' exemption in Sonoma County

The homeowners' exemption takes $7,000 off the taxable value of a home you live in on January 1. At the Santa Rosa example rate that is about $79.21 a year. You file form BOE-266 once with the Sonoma County Assessor; file by February 15 to get the full exemption for that year. Call the assessor at (707) 565-1888 if your bill does not show it.

Disabled veterans' exemption in Sonoma County

Veterans rated 100% disabled by the VA, or paid at the 100% rate for unemployability, can remove a much larger amount from the value of their principal home. There is a basic level and a low-income level, both indexed each year by the BOE. An unmarried surviving spouse may also qualify. Ask the Sonoma County Assessor for the current-year amounts and the BOE-261-G claim form.

School parcel tax exemptions in Sonoma County

Several Sonoma school districts levy flat parcel taxes, and some offer exemptions that the ad valorem bonds do not. The ACTTC's school parcel tax exemption page says qualified school taxes may exempt owners 65 or older and people receiving SSI for a disability. You apply to the district, not the county. Districts listed include Cotati-Rohnert Park Unified, Kenwood, Petaluma City Elementary, Petaluma Joint Union High, Rincon Valley, Sebastopol, Fort Ross, Shoreline Unified and West Sonoma County Union High. Bonds based on property value, by contrast, have no senior exemption.

Prop 19 transfers and disaster relief in Sonoma County

Prop 19 governs two things Sonoma owners ask about most: inheriting a parent's home and moving a low tax base to a new home. The full rules are on our Prop 19 guide. Locally, claims go to the Sonoma County Assessor, which links the BOE's Prop 19 pages and its own forms from the Tax Savings page.

Moving a Sonoma base year value

Owners who are 55 or older, severely disabled, or whose home was destroyed in a disaster can carry their factored base year value to a replacement home anywhere in California, up to three times for the age-based transfer. If the new home costs more than the old one sold for, the difference is added to the transferred value. A Santa Rosa owner moving to Windsor and one moving to another county file the same way: with the assessor of the county where the replacement home is.

Calamity reassessment after Sonoma fires and floods

Sonoma County has a separate calamity process for owners whose homes are damaged. The ACTTC's calamity reassessment FAQ says relief applies to damage over $10,000 and that you have 12 months from the event to file the Application for Reassessment of Property Damaged by Calamity. A home rebuilt in a like or similar manner keeps its prior factored base year value whatever the rebuild costs; added square footage is assessed at market value.

Supplemental tax bills after you buy in Sonoma County

The ACTTC's supplemental property tax page explains that state law reassesses a property on the first day of the month after a change in ownership or completed new construction. A remodel that restores a kitchen to new condition, a new room, a pool or a garage can trigger one. The county advises owners with impound accounts to ask their lender about paying supplemental bills.

Example supplemental bill for a Santa Rosa purchase

Suppose you close on March 15 at $782,980 and the seller's assessed value was $350,000. The new value takes effect April 1. The difference is $432,980. At 1.1315%, a full year on that difference is $4,899.17. Three months remain in the fiscal year (April to June), so the first supplemental bill is about $1,224.79. Because the purchase fell between January 1 and May 31, a second supplemental bill covers the full next fiscal year, since that year's roll was set on January 1 at the old value. These are estimates; the county calculates the real bill.

When Sonoma supplemental bills are due

Supplemental bills arrive throughout the year and have their own due and delinquency dates printed on them. They do not follow the November and February calendar of the annual bill.

Special taxes, parcel taxes and Mello-Roos in Sonoma County

Below the percentage rates, a Sonoma County bill lists direct charges: flat parcel taxes, fire and EMS assessments, sewer and water charges, and any Mello-Roos community facilities district (CFD) special tax. These are set per parcel or per unit, so two homes with the same assessed value in the same TRA can pay different totals. Our Mello-Roos guide explains how CFD taxes are capped and how they end.

Checking direct charges on a Sonoma home

• Ask the seller or title company for the most recent full-year secured bill and read the direct charge lines.
• Look at the Natural Hazard and tax disclosure report in escrow, which lists any CFD or 1915 Act assessment district.
• For a school parcel tax, call the district listed on the bill and ask whether you qualify for its senior or disability exemption.
• For newer subdivisions, ask the city's finance department whether the tract is in a CFD and request its rate and method of apportionment.

Where Sonoma property tax dollars go

The ACTTC's Property Tax Accounting Division reports that schools receive $631.5 million (48%), the county $355.7 million (27%), cities $121.4 million (9%), special districts $108.4 million (8%) and redevelopment-related activity $102.2 million (8%) of the distribution amounts it shows for FY 2026-27. Neither the Board of Supervisors nor the Tax Collector sets your tax amount; the rates and assessed values do.

Paying Sonoma County property tax: deadlines and options

Sonoma County's Due Dates and Penalties page sets out the secured calendar. You can pay both installments at once with the first.

If a delinquency date falls on a weekend, the deadline moves to 5:00 p.m. on the next business day. Payments left in the county drop box after 5:00 p.m. on the due date count as late. A late installment adds a 10% penalty, and a late second installment also adds a cost charge.

Sonoma County payment methods and fees

Online payments by e-check are free. Credit and debit card payments carry a 2.34% fee paid to the processor, and a returned payment costs $30. The county also offers monthly payments through Easy Smart Pay and paperless e-Tax bills through MyCountyConnect, where you sign in with a Google, Microsoft or Amazon account. Paper bills come with preaddressed envelopes for each installment. Questions go to the Tax Collector at (707) 565-2281 or taxcollector@sonomacounty.gov.

Appealing a Sonoma County assessment

Appeals go to the Sonoma County Assessment Appeals Board, run through the Board of Supervisors' office. The county's assessment appeals page says you must file between July 2 and November 30 to challenge the regular roll value. The BOE's 2026 filing-period letter confirms November 30, 2026 for Sonoma.

What to expect at a Sonoma appeal hearing

The board has worked through a backlog and the county estimates a 6 to 18 month wait for a hearing. It set eleven hearing dates for 2026, from January 23 to December 4. You need a separate application for each year you dispute, even if an earlier one is still pending. Keep paying your installments while you wait; a successful appeal brings a refund.

Before you file in Sonoma County

Check the enrolled value on the assessor's site when the roll posts around July or August. Gather sales of similar homes close to January 1. Many owners ask the assessor for an informal decline-in-value review first, which can settle the question without a hearing. Statewide appeal rules are on our California property tax guide, and county prices are on the Sonoma County data page.