Contra Costa County Property Tax Rates by City, Area, and Tax District 2026
Contra Costa County has a median effective property tax rate of 0.8309%, with a median annual property tax bill of $6,903. Actual bills vary by assessed value, tax rate area, voter-approved bonds, special assessments, and the property’s location.
Effective Tax Rate
0.78%
Median Property Tax
$8,474
Tax per $100K
$780
Last Update
August 2026
Contra Costa County Property Tax 2026-27
Contra Costa County Property Tax Rate
Contra Costa County property tax rates vary by district in the provided data. Parcel bills can still include fixed charges, parcel taxes, CFD charges, or special assessments depending on the property.
Base rate
1.0000% general ad valorem tax.
District rates
Contra Costa County district rates vary from 1.0000% to 1.4835% in the provided data.
Direct charges
Special assessments and parcel charges are added separately.
Area
Representative Rate
Antioch District
1.1850%
Brentwood District
1.1450%
Clayton District
1.1120%
Concord District
1.1210%
Countywide-Unitary Base
1.0000%
Danville District
1.1080%
El Cerrito District
1.2640%
Hercules District
1.2150%
Lafayette District
1.1180%
Martinez District
1.1620%
Moraga District
1.1240%
Oakley District
1.1340%
Orinda District
1.1360%
Pinole District
1.1980%
Pittsburg District
1.1710%
Pleasant Hill District
1.1230%
Richmond District
1.2820%
San Pablo District
1.2410%
San Ramon District
1.1090%
Unincorporated Area District
1.0000%
Walnut Creek District
1.1140%
Other Contra Costa County Property Tools
Property tax research is easier when you can review the parcel itself alongside its tax information, location, ownership details, and applicable property characteristics.
Contra Costa County Property Search
Search property records using an owner name, address, parcel number, city, ZIP code, or other available property filters.
Contra Costa Property Tax Calculator
Estimate annual property taxes by entering a property value and using relevant property tax rate information.
Contra Costa Doc Stamp Calculator
Estimate documentary transfer taxes or related charges that may apply to qualifying recorded real estate transactions.
Contra Costa County Zoning and Maps
Explore parcel locations, zoning information, maps, boundaries, and other geographic details connected with a property.
How Property Tax Rates Are Applied
The tax calculation begins with the property’s assessed value rather than simply its current market price. Under California’s Proposition 13 system, a property’s taxable assessment generally starts with its base-year value and is subject to limited annual adjustments. The applicable tax rate and additional charges are then used to determine the amount shown on the tax bill.
Assessed Value and Taxable Value
The County Assessor determines assessed value for property taxation. Exemptions can reduce the taxable value used to calculate ad valorem taxes, while Proposition 13 generally limits annual increases to the factored base-year value.
Applying the Tax Rate
The basic property tax is generally calculated at 1% of assessed value, with additional voter-approved bond rates potentially added. The resulting amount is only part of the complete tax bill when other charges apply.
Tax Rate Areas
A parcel’s tax rate area identifies the combination of taxing jurisdictions associated with that location. In Contra Costa County, tax rate areas help determine how the countywide tax base and applicable local charges relate to individual properties.
Special Assessments and Charges
Property tax bills can contain special taxes, assessments, fees, and direct charges in addition to ad valorem property taxes. These amounts can support specific services or programs and may differ substantially between neighboring areas.
Ownership Changes Can Trigger Reassessment
A change in ownership generally causes the property to be reassessed under California law. The new assessment is based on the property’s value at the time of the qualifying ownership change, subject to applicable exclusions.
Supplemental Tax Bills
Buying property or completing substantial new construction can create a supplemental assessment. Contra Costa County may issue one or more supplemental bills covering the difference between the prior assessment and the newly assessed value for the applicable period.
Why Property Tax Rates Vary Across Districts
Contra Costa County spans established cities, suburban communities, waterfront areas, and eastern Delta locations. Different combinations of local agencies and voter-approved measures serve these areas, so the total tax burden can change from one parcel to another.
- Tax districts exist so specific local agencies can fund services provided within defined geographic boundaries.
- Local services such as schools, sanitation, fire protection, and other programs can influence applicable property tax charges.
- Each tax rate area combines the taxing jurisdictions and approved charges associated with a particular geographic location.
- Two nearby properties can have different bills because their parcels fall within different tax rate areas.
- Voter-approved bonds and special taxes can add charges that continue until their authorized obligations or terms end.
- The parcel's exact location determines which local agencies, assessments, and voter-approved charges appear on its tax bill.
Compare Property Tax Rates in Nearby California Counties
Comparing nearby counties can help buyers, homeowners, investors, and researchers understand how property tax burdens differ across the surrounding Bay Area and Delta region. California Property Checker provides county-specific property information and tools for researching properties across California.
Frequently Asked Questions
Does buying a property change its assessed value?
Usually, yes. A qualifying change in ownership generally causes the Assessor to establish a new base-year value based on the property’s market value at the time of the change. Certain legally defined transfers may qualify for exclusions from reassessment.
Can my property tax increase after a home improvement?
Yes. Substantial new construction or improvements that qualify as new construction can result in reassessment. Routine maintenance generally does not create a new assessment, but substantial additions or alterations may produce a supplemental assessment.
What is a supplemental property tax bill?
A supplemental bill covers the additional property tax resulting from a change in assessed value after a qualifying ownership change or completion of new construction. It is separate from the regular annual secured property tax bill.
When are Contra Costa County property taxes due?
For secured property taxes, the first installment is due November 1 and becomes delinquent after December 10. The second installment is payable by February 1 and becomes delinquent after April 10. The county allows both installments to be paid by December 10.
What happens if property taxes are paid late?
Late secured-property-tax installments generally receive a 10% penalty. A late second installment can also carry an additional administrative charge. Supplemental tax bills follow their own printed delinquency dates based on when the bill was mailed.
How can I dispute my property's assessed value?
Property owners can contact the Assessor regarding valuation concerns and may have appeal rights through the County Assessment Appeals Board. Regular assessment appeals in Contra Costa County are generally filed between July 2 and November 30.
Is there a Homeowners' Exemption in Contra Costa County?
Eligible homeowners who own and occupy a property as their principal residence can claim a $7,000 exemption from assessed value. The county indicates this can reduce annual property taxes by approximately $70.
Can a lower property value reduce my property taxes?
Potentially. California allows certain properties to receive a temporary assessment reduction when current market value falls below the property’s applicable Proposition 13 factored base-year value. The Assessor determines whether the property qualifies for a reduced assessment.
Where can I verify my actual property tax bill?
The official Contra Costa County Tax Collector’s property tax services allow property owners to review tax information, payment details, and tax history. California Property Checker can also help with broader property research, but it is not the official tax authority.
Why is an estimated tax calculation different from my actual bill?
An estimate may use a countywide effective rate, while an actual bill is based on the property’s assessed value and exact tax rate area. Special taxes, bonds, exemptions, assessments, and other parcel-specific charges can make the final amount different.