Property Tax in Contra Costa County, California
Homeowners in Contra Costa County, California pay a median of $6,903 a year in real estate taxes, on a median home value of $830,800. Those are the Census Bureau's published medians for the county (US Census Bureau, American Community Survey (ACS) 5-year estimates, 2023) — the typical bill and the typical home value for owner-occupied households.
What the Contra Costa County numbers mean
A median is the middle household: half of owner-occupied households in Contra Costa County pay more than $6,903, and half pay less. Your own bill is set by your home's assessed value, the exemptions you qualify for, and the local taxing districts your property sits in — so individual bills vary widely around the median.
Dividing the median tax by the median home value gives a derived effective rate of 0.83% for Contra Costa County. It is an estimate built from two survey medians, not the county's official rate, but it is a fair way to compare the local tax burden with other counties where home values are very different.
Contra Costa County by the numbers
| Measure | Contra Costa County | California | United States |
|---|---|---|---|
| Median real estate taxes paid | $6,903 | $4,926 | $2,969 |
| Median home value | $830,800 | $695,400 | $303,400 |
| Derived effective rate* | 0.83% | 0.71% | 0.98% |
| Median tax per month | $575 | $410 | $247 |
*Estimate derived from Census medians (tax ÷ value), not an official rate.
Contra Costa County at a glance
- Median tax rank in California: #6 of 58 counties
- Median home value rank in California: #9 of 58
- Population rank in California: #9 of 58 (1,161,458 residents)
- Population density rank: #7 of 58 (1,620 people per square mile)
- Land area rank in California: #51 of 58 (716 sq mi, 0.5% of the combined county land area)
- Median tax as a monthly figure: $575; per $1,000 of home value: $0.83
How Contra Costa County compares
Set against its state, Contra Costa County's median bill of $6,903 is about 40% higher than the California median ($4,926). Against the country as a whole it is about 133% higher than the US median ($2,969). That places the county #6 of 58 California counties ranked by median taxes paid.
Remember what drives the ranking: bills follow home values as much as rates. Contra Costa County's median home, at $830,800, ranks #9 by value in California, while its derived rate of 0.83% compares with a derived US figure of 0.98%.
Some extra context for Contra Costa County: the median bill works out to about $575 a month, and the derived rate equals roughly $831 of tax per $100,000 of home value. The county is home to 1,161,458 people — the #9 most populous county in California, spread over 716 square miles, a density of about 1,620 people per square mile. Its median home value, $830,800, ranks #9 among the state's 58 counties with data.
Zooming out: of 3133 counties nationwide with published Census figures, only 48 record a higher median tax bill than Contra Costa County — it sits in the top 2% nationally. The county holds roughly 3.0% of California's people. Its homes are worth more than the state norm (median $830,800 versus $695,400), and a decade at the derived rate of 0.83% adds up to about 8.31% of the median home's value in tax. The cheapest county in the state, Modoc County, medians $1,445 — $5,458 less than Contra Costa County per year.
Counties nearest Contra Costa County in the California ranking
| County | Median tax paid | Median home value | Derived rate* |
|---|---|---|---|
| San Mateo County, CA | $9,167 | $1,494,500 | 0.61% |
| Alameda County, CA | $8,061 | $1,057,400 | 0.76% |
| Santa Cruz County, CA | $6,305 | $1,015,200 | 0.62% |
| Orange County, CA | $6,096 | $915,500 | 0.67% |
How the tax is worked out
As an illustration of the arithmetic: at Contra Costa County's derived rate of 0.83%, a home valued at $400,000 would carry a tax bill of roughly $3,324 a year. That is only an illustration using the derived rate — a real bill is computed from the property's assessed value, its exemptions, and the combined rates of its specific taxing districts, so it can be higher or lower.
The usual sequence is: the local assessor values the property; exemptions are applied; the taxable value is multiplied by the combined local rates; and the county bills and collects the tax, distributing it to the schools, municipalities and districts that levied it.
Checking your assessment in Contra Costa County
Most successful appeals are won on facts, not arguments. Start with the property record card held by the Contra Costa County assessor: wrong square footage, an extra room, or a missing homestead exemption are common and fixable. Next, line your assessed value up against recent sales of genuinely similar homes nearby. Many disputes end at an informal conversation with the assessor's office; if yours does not, file the formal appeal with the review board named on your notice before its deadline, evidence attached, and keep paying the bill in the meantime so penalties do not build up.
More California counties
Frequently asked questions
What is the median property tax in Contra Costa County, California?
The median real estate tax paid in Contra Costa County, California is $6,903 per year, on a median home value of $830,800 (US Census Bureau, American Community Survey (ACS) 5-year estimates, 2023).
What is the effective property tax rate in Contra Costa County, California?
The derived effective rate is 0.83% — the median bill ($6,903) expressed as a share of the median home value ($830,800). No authority sets a rate this way; it exists to make counties with different home prices comparable.
How does Contra Costa County compare with the rest of California?
Contra Costa County ranks #6 of 58 California counties with published data by median taxes paid. Its median bill of $6,903 is about 40% higher than the California median of $4,926.
How are property taxes calculated in Contra Costa County, California?
Three steps produce the bill: an assessment of market value by the local assessor, a reduction for exemptions you qualify for (a homestead exemption is the common one), and multiplication by the combined rates of the county, municipality, school district and any special districts covering the property. The median result in Contra Costa County is $6,903 of tax on a $830,800 median home value.
Can I appeal my property tax assessment in Contra Costa County, California?
Yes. Request your property record card from the Contra Costa County assessor's office and check it for errors, then compare your assessed value with recent sales of similar homes. If it still looks too high, file a formal appeal with the local review board named on your assessment notice before the deadline printed on the notice — windows are short, often 30 to 90 days.