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Port Costa, Contra Costa County, California Property Taxes

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Property Taxes in Port Costa, California

  • Median Port Costa, California effective property tax rate: 1.73%, significantly higher than the national median of 1.02%, and higher than the California state median of 1.21%.

  • Median Port Costa, California home value: $421,753

  • Median annual Port Costa, California tax bill: $7,139, $4,739 higher than the national median property tax bill of $2,400.

How are property taxes in Contra Costa calculated?

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

Last Updated April 13, 2026

Port Costa, Contra Costa County, California Property Tax Bill Calculator

$100,000

$1,500,000

$3,000,000

Median Effective Tax Rate

1.73%

Estimate Property Tax Bill

$7,296

$6,771

SAVE WITH OWNWELL

$774

Average Annual Tax Savings

How Does the Port Costa Property Tax Calculator Work?

Use this Port Costa property tax calculator to estimate your annual tax bill. Enter your property's assessed value and our calculator applies Port Costa's median effective tax rate of 1.73% — based on actual property records in Contra Costa County — to generate your estimate.

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

Your bill may vary by ZIP code within Port Costa: rates range from 1.73% in 94569 to 1.73% in 94569, primarily due to differences in school district levies and local assessment districts.

Port Costa's median property tax rate is higher than the California median rate of 1.21%, and the median property tax bill of $7,139 is higher than the national median property tax bill of $2,400. If your estimate is higher than expected, Ownwell can appeal your Port Costa assessment — you only pay if we save you money.

About Port Costa Property Taxes

About Property Taxes in Port Costa, Contra Costa, California

Port Costa’s median effective property tax rate of 1.73% is higher 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 Mello-Roos Community Facility Districts that vary by subdivision throughout the city.

Property tax rates are not uniform across Port Costa. Homeowners in ZIP code 94569 carry a median effective rate of 1.73%, while those in 94569 pay 1.73%. This spread — 0 percentage points across the same city — reflects how school district boundaries and local assessment districts are drawn across Contra Costa County. Understanding which part of Port Costa you live in can make a meaningful difference to your annual tax bill.

Port Costa homeowners who believe their assessed value is too high can file a formal appeal with the local Tax Assessor before December 1, 2026.

If your estimated bill above 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 Port Costa, 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 Port Costa'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 Port Costa, 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 Port Costa Tax Rate

1.73%

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 Port Costa, Contra Costa County, California

Zip10th Percentile25th PercentileMedian Tax Rate75th Percentile90th Percentile
945691.42%1.53%1.73%2.44%5.63%

Source: Ownwell

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

When examining property taxes in Port Costa, 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 assessment office 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 October 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 Port Costa.

For example, the median home price in Port Costa is $421,753, with tax bills ranging significantly across the county. 94569 has the highest median home price at $421,753.

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

Source: Ownwell

$153,114

$1,176,704

$2,200,294

Median Port Costa Market Value

$421,753

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 Port Costa, Contra Costa County, California

Zip10th Percentile25th PercentileMedian Home Price75th Percentile90th Percentile
94569$69,463$220,841$421,753$565,658$670,969

Source: Ownwell

Property Tax Bills Across Port Costa, Contra Costa County, California

Property tax bills in Port Costa are based on the assessed value of a home, not its market price alone. Local tax rates are applied to that assessed value, and the final bill can also reflect exemptions and other local factors. With a median home price of $421,753, homeowners in this area often face bills that are well above the national median property tax bill of $2,400.

For many homeowners, the tax bill is a major part of annual housing costs. In Port Costa, the 25th percentile tax bill is $5,086, the 75th percentile is $8,654, and the 90th percentile is $9,561. The median tax bill in ZIP code 94569 is $7,139, showing how quickly property taxes can add up.

Ownwell helps homeowners lower property tax bills by reviewing assessments for errors and identifying opportunities for savings. If your home is overassessed, an appeal can reduce what you owe and help keep more money in your pocket each year.

Property Tax Bills Across Port Costa, Contra Costa County, California

Source: Ownwell

$3,003

$13,751

$24,499

Median Port Costa Tax Bill

$7,139

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 Port Costa, Contra Costa County, California

Zip10th Percentile25th PercentileMedian Tax Bill75th Percentile90th Percentile
94569$3,601$5,086$7,139$8,654$9,561

Source: Ownwell

Don't miss the deadline to appeal!

Frequently Asked Property Tax Questions in Port Costa, California

How are property taxes calculated in Port Costa, California?
Property taxes in Port Costa, 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 Port Costa, California?
To appeal your property taxes in Port Costa, 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 Port Costa, California?
Common property tax exemptions in Port Costa, 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 Port Costa, California?
Property tax deadlines in Port Costa, 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 Port Costa, California?
Ownwell provides professional property tax appeal services in Port Costa, 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.