In tax year 2026, the median homeowner in Contra Costa County paid $6,979 in California property taxes, representing a median effective rate of 1.31% of market value, compared with 1.21% statewide. Under Prop 13, homes are assessed based on their purchase price base year value, and annual assessment increases are capped at 2% per year.
In Contra Costa County, rates range from 1.05% in Knightsen to 1.82% in Richmond.
- Median Contra Costa County effective property tax rate: 1.31%
- Median Contra Costa County home value: $530,390
- Median Contra Costa County property tax bill: $6,979
Last Updated October 26, 2026
How Property Taxes Work in Contra Costa County
Under Proposition 13, the base property tax rate across California is constitutionally capped at 1% of assessed value, plus voter-approved local bonds and special assessments. A home's assessed value is initially established at its purchase price (the base year value) and can only increase by up to 2% per year until the property undergoes a change in ownership or new construction occurs.
Because assessments reflect historic acquisition values rather than current market pricing, longtime homeowners in Contra Costa County often pay substantially less in property taxes than recent buyers of identical homes. If market conditions decline and your home's actual market value drops below its factored base year value as of January 1, Proposition 8 authorizes a temporary decline-in-value reduction to match current market conditions.
Our median effective property tax rate (tax bill ÷ assessor's market value) accounts for exemptions and deductions, making it more accurate than the general median tax rate, which is the midpoint of statutory rates before adjustments.
Median Contra Costa County Effective Property Tax Rate
1.31%
Median Contra Costa County Home Value
$530,390
Median Contra Costa County Tax Bill
$6,979
What is the Median Effective Property Tax Rate?
Our median effective property tax rate (tax bill ÷ assessor's market value) accounts for exemptions and deductions, making it more accurate than the general median tax rate, which is the midpoint of statutory rates before adjustments.
Because Prop 13 locks assessed values to historic purchase prices rather than current fair market value, statutory millage rates do not paint an accurate picture; the effective rate is the only reliable way to evaluate the true property tax burden across Contra Costa County and California.
Property Tax Rates and Bills by City
| Rank | City | Median Effective Tax Rate | Median Home Value | Median Tax Bill | 25th % Bill | 75th % Bill | 90th % Bill |
|---|---|---|---|---|---|---|---|
| 1 | Diablo | 1.14% | $2,200,294 | $24,499 | $15,986 | $37,213 | $50,172 |
| 2 | Pleasanton | 1.07% | $1,624,324 | $17,424 | $13,116 | $31,954 | $44,463 |
| 3 | Alamo | 1.13% | $1,520,246 | $16,884 | $10,498 | $23,859 | $32,141 |
| 4 | Orinda | 1.28% | $1,283,325 | $15,978 | $9,382 | $22,922 | $31,795 |
| 5 | Lafayette | 1.22% | $1,107,041 | $13,289 | $7,726 | $19,959 | $27,628 |
| 6 | Danville | 1.17% | $1,106,878 | $12,664 | $8,275 | $18,102 | $24,315 |
| 7 | San Ramon | 1.25% | $971,490 | $12,051 | $7,491 | $16,947 | $21,614 |
| 8 | Kensington | 1.47% | $823,272 | $11,783 | $6,585 | $16,928 | $22,146 |
| 9 | Moraga | 1.27% | $935,877 | $11,552 | $7,404 | $17,111 | $22,042 |
| 10 | Berkeley | 1.53% | $703,544 | $10,993 | $7,228 | $13,318 | $19,925 |
| 11 | Livermore | 1.10% | $799,103 | $8,794 | $5,205 | $15,886 | $21,245 |
| 12 | El Cerrito | 1.46% | $614,856 | $8,670 | $5,126 | $12,663 | $16,748 |
| 13 | Discovery Bay | 1.33% | $645,246 | $8,516 | $6,695 | $10,227 | $12,128 |
| 14 | Clayton | 1.24% | $690,066 | $8,515 | $5,664 | $11,141 | $13,525 |
| 15 | Briones | 1.11% | $754,921 | $8,392 | $4,792 | $12,294 | $19,248 |
| 16 | Brentwood | 1.32% | $608,634 | $8,119 | $5,709 | $10,697 | $12,801 |
| 17 | Hercules | 1.58% | $466,154 | $7,279 | $5,312 | $10,293 | $13,024 |
| 18 | Pleasant Hill | 1.24% | $591,094 | $7,189 | $4,434 | $10,109 | $12,816 |
| 19 | Port Costa | 1.73% | $421,753 | $7,139 | $5,086 | $8,654 | $9,561 |
| 20 | Oakley | 1.50% | $488,936 | $6,999 | $4,512 | $10,616 | $12,842 |
| 21 | El Sobrante | 1.61% | $426,681 | $6,731 | $4,574 | $9,537 | $12,072 |
| 22 | Martinez | 1.32% | $478,326 | $6,229 | $4,110 | $8,693 | $10,899 |
| 23 | Pinole | 1.55% | $405,000 | $6,168 | $4,423 | $8,698 | $10,637 |
| 24 | Richmond | 1.82% | $340,732 | $6,146 | $3,839 | $9,153 | $11,864 |
| 25 | Crockett | 1.45% | $406,200 | $5,720 | $4,071 | $7,858 | $9,433 |
| 26 | Rodeo | 1.60% | $355,281 | $5,647 | $4,185 | $7,759 | $9,350 |
| 27 | Bethel Island | 1.37% | $422,145 | $5,602 | $2,726 | $11,713 | $23,322 |
| 28 | Concord | 1.29% | $423,375 | $5,388 | $3,498 | $8,087 | $10,157 |
| 29 | San Pablo | 1.70% | $317,564 | $5,177 | $3,485 | $7,743 | $10,003 |
| 30 | Antioch | 1.23% | $409,613 | $4,875 | $3,323 | $6,573 | $8,284 |
| 31 | Bay Point | 1.42% | $339,308 | $4,632 | $2,847 | $7,303 | $10,582 |
| 32 | Knightsen | 1.05% | $457,691 | $4,604 | $1,905 | $7,605 | $11,883 |
| 33 | Pittsburg | 1.32% | $339,498 | $4,328 | $2,760 | $6,337 | $8,277 |
| 34 | Pacheco | 1.26% | $317,306 | $4,206 | $1,723 | $6,915 | $8,620 |
| 35 | Byron | 1.17% | $310,424 | $3,799 | $1,585 | $6,329 | $8,968 |
| 36 | Canyon | 1.16% | $273,826 | $3,047 | $1,314 | $5,718 | $10,001 |
| — | Albany | N/A | N/A | N/A | N/A | N/A | N/A |
| — | Renton | N/A | N/A | N/A | N/A | N/A | N/A |
| — | Walnut Creek | N/A | N/A | N/A | N/A | N/A | N/A |
Source: Ownwell
How to Appeal Your Property Taxes in Contra Costa County
In California, you can file an appeal of your assessment if your home's fair market value as of the January 1 lien date is lower than its assessed value on the roll, or if the county incorrectly assessed your base year value. Formal appeals are filed with the Clerk of the Board and adjudicated by the Assessment Appeals Board (AAB).
Request an informal review
Many county assessors accept decline-in-value review requests in the spring and early summer. An appraiser can review recent neighborhood sales and may grant a temporary Proposition 8 reduction without requiring a formal hearing.
File an Assessment Appeal Application
If an informal review is unavailable or does not produce a fair valuation, submit Form BOE-305-AH to the Contra Costa County Clerk of the Board. The annual regular filing window opens July 2 and closes November 30.
Assemble market evidence
Collect recent sales of comparable properties that sold on or before the January 1 lien date (California law generally excludes comparable sales occurring more than 90 days after January 1). Appraisals and photo documentation of deferred maintenance or damage provide strong supporting evidence.
Attend the board hearing
Present your case before the Assessment Appeals Board (AAB) or an assessment hearing officer. The board evaluates evidence submitted by you and the assessor and determines the final taxable value.
Further appeal
An appeals board decision is legally final at the county level. If you disagree with the decision, you must first file a formal claim for refund with the Contra Costa County Board of Supervisors and subsequently pursue an action in California Superior Court within six months of rejection.
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California Property Tax Exemptions
California provides relief to primary homeowners through state-administered exemption and tax-base transfer rules:
- Homeowners' Exemption: The California homestead exemption deducts $7,000 from the assessed value of an owner-occupied principal residence, saving most homeowners approximately $70 annually on their property tax bill. File with the county assessor by February 15 for full relief.
- Disabled Veterans' Exemption: Provides a substantial exemption (with basic and low-income tiers adjusted annually for inflation) on the principal residence of 100% disabled veterans or their unmarried surviving spouses.
- Proposition 19 Base Year Transfers: Homeowners age 55 and older, severely disabled individuals, and victims of wildfires or natural disasters can transfer their Prop 13 base year value to a replacement residence anywhere within California up to three times.
- Proposition 19 Intergenerational Transfers: Limits parent-to-child and grandparent-to-grandchild property tax exclusions exclusively to family homes used by the child as a principal residence, subject to a value cap.
Key Dates
| Date | What Happens |
|---|---|
| January 1 | Lien date; property assessed for the upcoming tax year |
| February 15 | Homeowners' Exemption application deadline for full benefit |
| July 2 | Regular assessment appeal filing window opens statewide |
| November 30 | Regular assessment appeal filing deadline in Contra Costa County |
| November 1 | First installment of secured property taxes due (delinquent after December 10) |
| February 1 | Second installment of secured property taxes due (delinquent after April 10) |
Frequently Asked Property Tax Questions in Contra Costa County
What is the average property tax rate in Contra Costa County?
Which city in Contra Costa County has the highest and lowest property taxes?
How does Prop 13 affect property taxes in Contra Costa County?
When is the property tax appeal deadline in Contra Costa County?
What is a Proposition 8 decline-in-value review?
Who hears property tax appeals in Contra Costa County?
When are property taxes due in California?
Is it worth appealing property taxes in Contra Costa County?
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