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Diablo, Contra Costa County, California Property Taxes

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Property Taxes in Diablo, California

  • Median Diablo, California effective property tax rate: 1.14%, significantly higher than the national median of 1.02%, and lower than the California state median of 1.21%.

  • Median Diablo, California home value: $2,200,294

  • Median annual Diablo, California tax bill: $24,499, $22,099 higher than the national median property tax bill of $2,400.

How are property taxes in Contra Costa calculated?

Property taxes in Diablo, California are calculated based on the tax assessed value, which is often lower than the actual market value due to property tax exemptions such as the homestead or senior exemption.

Understanding Diablo's property tax system, exemptions, and reduction opportunities can lead to significant savings. Regardless of where you live in Diablo, knowing local tax details benefits homeowners and investors.

Last Updated April 13, 2026

Diablo, Contra Costa County, California Property Tax Bill Calculator

$100,000

$1,500,000

$3,000,000

Median Effective Tax Rate

1.14%

Estimate Property Tax Bill

$25,083

$23,277

SAVE WITH OWNWELL

$774

Average Annual Tax Savings

How Does the Diablo Property Tax Calculator Work?

Use this Diablo property tax calculator to estimate your annual tax bill. Enter your property's assessed value and our calculator applies Diablo's median effective tax rate of 1.14% — based on actual property records in Contra Costa County — to generate your estimate.

Enter your property's estimated assessed value — the figure the local appraisal district uses to calculate your bill, which reflects any exemptions you hold and is typically lower than your home's market value. Our calculator applies Diablo's median effective rate across all local levies, providing a more accurate estimate than applying a single county millage rate.

Your bill may vary by ZIP code within Diablo: rates range from 24499.00% in 94528 to 24499.00% in 94528, primarily due to differences in school district levies and local assessment districts.

If your estimate is higher than expected, Ownwell can appeal your Diablo assessment — you only pay if we save you money.

About Diablo Property Taxes

About Property Taxes in Diablo, Contra Costa, California

Diablo’s median effective property tax rate of 1.14% is lower than the California state median of 1.21% and higher than the national median of 1.02%. This rate reflects the Contra Costa County base levy combined with local school district levies and other local assessments that can affect what homeowners pay.

Property tax rates are not uniform across Diablo. Homeowners in the 94528 ZIP code carry a median effective rate of 1.14%, and the same ZIP also reflects the city’s median home price of $2,200,294 and median tax bill of $24,499. Understanding how your assessed value is set can make a meaningful difference to your annual tax bill.

Diablo homeowners who believe their assessed value is too high can file a formal appeal with the Tax Assessor before the December 1, 2026 deadline each year, after notices are sent in October.

If your estimated bill seems higher than expected, Ownwell can review your assessment and protest on your behalf. You only pay if we save you money.

Property Tax Rates Across Diablo, Contra Costa County, California

As noted earlier, local government entities set tax rates, which can vary widely within a state.

Why? Because annually, each county estimates its required budget to provide services and divides that by the total value of all taxable property within its jurisdiction. This calculation results in the property tax rate.

While there are votes and laws involved in setting tax rates and budgets, in a nutshell, this is the annual process.

Below, you can compare Diablo's effective property tax rate to other cities in California and the median property tax rates in California and the U.S.

Property Tax Rates Across Diablo, Contra Costa County, California

Source: Ownwell

1.05%

1.46%

1.87%

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 Effective Diablo Tax Rate

1.14%

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 Effective Contra Costa County Tax Rate

1.31%

Median Effective California Tax Rate

1.21%

Median Effective United States Tax Rate

1.02%

Property Tax Rates Across Diablo, Contra Costa County, California

Zip10th Percentile25th PercentileMedian Tax Rate75th Percentile90th Percentile
945281.09%1.11%1.14%1.19%1.36%

Source: Ownwell

Property Tax Assessment Values Across Diablo, Contra Costa County, California

When examining property taxes in Diablo, California, understanding the distinction between "market value" and "assessed value" is crucial.

The market value is what a willing buyer would pay to a willing seller in an open and competitive market, often influenced by location, property condition, and economic market trends. The Contra Costa County appraisal district estimates the market value for tax purposes.

The assessed value is the market value minus any applicable exemptions or limits determined by local laws and offerings. The tax assessed value is the figure used to calculate your property taxes or the amount multiplied by your tax rate to get your tax bill.

Assessment notices:

In Contra Costa County, assessment notices are sent in the spring each year. They'll typically reach your mailbox by the middle of October.

Each property owner receives an assessment notice that contains both the market value and assessed value, along with an estimate of your property tax bill. By providing insights into how assessed and market values are determined, this section helps property owners navigate their tax responsibilities and understand the valuation processes affecting their property taxes in Diablo.

For example, the median home price in Diablo is $2,200,294, with tax bills ranging significantly across the county. 94528 has the highest median home price at $2,200,294.

Property Tax Assessment Values Across Diablo, Contra Costa County, California

Source: Ownwell

$153,114

$1,176,704

$2,200,294

Median Diablo Market Value

$2,200,294

Median Contra Costa County Market Value

$530,390

Median California Market Value

$427,605

Median United States Market Value

$235,294

Property Tax Assessment Values Across Diablo, Contra Costa County, California

Zip10th Percentile25th PercentileMedian Home Price75th Percentile90th Percentile
94528$548,675$1,392,999$2,200,294$3,363,143$4,632,031

Source: Ownwell

Property Tax Bills Across Diablo, Contra Costa County, California

Property tax bills in Diablo are based on the assessed value of a home, which is influenced by its market value and local tax rates. With a median home price of $2,200,294, homeowners in this area often face substantial property tax bills, especially when compared with the national median property tax bill of $2,400 and the national median property tax rate of 1.02%. The 25th percentile tax bill is $15,986, while the 75th percentile reaches $37,213, and the 90th percentile climbs to $50,172. In zip code 94528, the median tax bill is $24,499. These bills can significantly affect monthly housing costs and long-term affordability.

Ownwell helps homeowners lower their property tax bills by reviewing assessments and identifying opportunities to appeal overassessed values. By making sure your property is taxed fairly, Ownwell can help reduce what you owe and keep more money in your pocket.

Property Tax Bills Across Diablo, Contra Costa County, California

Source: Ownwell

$3,003

$13,751

$24,499

Median Diablo Tax Bill

$24,499

Median Contra Costa County Tax Bill

$6,979

Median California Tax Bill

$5,134

Median United States Tax Bill

$2,400

Property Tax Bills Across Diablo, Contra Costa County, California

Zip10th Percentile25th PercentileMedian Tax Bill75th Percentile90th Percentile
94528$7,620$15,986$24,499$37,213$50,172

Source: Ownwell

Don't miss the deadline to appeal!

Frequently Asked Property Tax Questions in Diablo, California

How are property taxes calculated in Diablo, California?
Property taxes in Diablo, California are calculated by multiplying your property's assessed value by the applicable tax rate set by local taxing authorities. The assessed value is determined by the county assessor and may differ from your property's market value depending on local assessment ratios and exemptions.
How do I appeal my property taxes in Diablo, California?
To appeal your property taxes in Diablo, California, you typically need to file a formal protest or appeal with your local appraisal district or assessor's office by the stated deadline. You'll need evidence such as comparable sales, a recent independent appraisal, or documentation of property condition issues. Ownwell can handle this entire process for you.
What property tax exemptions are available in Diablo, California?
Common property tax exemptions in Diablo, California include homestead exemptions for primary residences, senior citizen exemptions, veteran exemptions, and disability exemptions. Exemption amounts and eligibility requirements vary by county. Contact your local appraisal district or check Ownwell for details specific to your property.
When are property taxes due in Diablo, California?
Property tax deadlines in Diablo, California vary by county but typically include an assessment notice period in spring or early summer, followed by an appeal deadline, and a tax payment due date in the fall or winter. Check with your county assessor's office for specific dates in your area.
How can Ownwell help reduce my property taxes in Diablo, California?
Ownwell provides professional property tax appeal services in Diablo, California. Our team analyzes your assessment, gathers evidence, files all paperwork, and represents you at hearings — all with no upfront cost. You only pay a percentage of your savings if we successfully lower your tax bill.