How do you calculate taxes?

The taxes are calculated by the Auditor-Controller. Property tax rates vary by area. In Contra Costa County the tax rates average approximately 1.1% of the property's taxable value. For instance, if the taxable value is $10,000, the property taxes could be about $110. Contact the Auditor-Controller at(925) 646-2236 or

Auditor-Controller

Show All Answers

1. My property value was reduced under Proposition 8. Now the Assessment has increased. Why?
2. What is a Supplemental Assessment?
3. What about NEW CONSTRUCTION reappraisals?
4. Is property assessed at the price paid?
5. Are there special programs available for Senior Citizens?
6. Is there a Builder's Exclusion?
7. I am over 55 and wish to move to a smaller home. Will my taxes go up?
8. What is the Williamson Act (Ag Preserve)?
9. When is Real Estate reappraised?
10. If I have an addition to my home, will you reappraise the entire property?
11. If I do the work myself, will I only be assessed on the cost of the materials?
12. Are mobile homes subject to property taxes?
13. When can I appeal my assessed value?
14. What and when is a lien date?
15. Why are my neighbor's and my tax bills different when the houses are the same?
16. What happens if I don't pay these taxes?
17. How do you calculate taxes?