Treasurer-Tax Collector
Find property tax bills, payment options and tax collection services. Find the local office for a business license or business tax certificate. Check the business activity and place covered by each service.[7]
Source checked October 12, 2026[1]www.contracosta.ca.gov
Opens this office’s own website. CountyWiki does not process applications, take payments or provide personal records.
Contact details & office locations ↓Online services & information
These links were found on official source pages. Each service is handled by the office.
Official Contra Costa County property-tax bill or payment portal. Follow the county’s instructions for your bill type and review the amount and any payment charges before paying.
Check where the business operates, including work in the unincorporated area by an outside business. Obtain required land-use approval before applying. Confirm fees and renewal timing with the county.
Service area: Business conducted in unincorporated Contra Costa County, including covered outside businesses and contractors. [9]
Before you start
- Eligibility & access
- City-only operations do not need a county business license under these instructions. Operations in both city and unincorporated areas may need both licenses. [10]
- Eligibility & access · Exemption applications
- Listed exemptions are not automatic: file the exemption application and proof annually. [14]
Use the official online application and attach the land-use approval notice when required. The Planning office at Muir Road is separate from the Tax Collector counter.
Service area: County application for the covered unincorporated-area business activity; check city and outside-contractor requirements separately. [12]
Before you start
- Information & documents · Businesses located in the unincorporated area
- Get the applicable Conservation and Development approval first and attach the approval notice to the application. [13]
Return the license with a written closure request, or use the mailbox the county designates for closure requests.
Service area: Closure of county licenses for business conducted in unincorporated Contra Costa County. [16]
Fees
Fees are quoted only when a source document supports the amount and conditions.
Check the official website for its current fee schedule. No fee should be assumed to be free.
Forms & documents
Official forms and document pages for this office’s services.
Sources & last checked4 source pages · 17 citations
Sources were checked by an AI-assisted research process. A checked website does not mean every service or fee on it has been reviewed.
- [1] Contra Costa County — departments directory (opens in a new tab)
Contra Costa County · Department directory: Treasurer-Tax Collector
Source reviewed October 12, 2026View supporting excerpt
Treasurer - Tax Collector
- [2] Contra Costa County — Treasurer-Tax Collector | Contra Costa County, CA Official Website (opens in a new tab)
Contra Costa County · Current county property-tax service heading or explicitly linked destination; bill type and payment channel are reviewed separately.
Source reviewed October 14, 2026View supporting excerpt
n M. Mierzwa Treasurer-Tax Collector Belinda Zhu Assistant Treasurer Public Response Form Tax Portal Property owners can look up property tax details, pay online, schedule payments, sign up for Paperless Billing and review tax history. View or Pay Now Property Tax Information General information regarding secured, unsecured, supplemental and other services the Tax Collector provides. Learn more >
- [3] Contra Costa County — Treasurer-Tax Collector | Contra Costa County, CA Official Website (opens in a new tab)
Contra Costa County · Tax Collector office — specific tax-collection contact block; visitor, mail, telephone and branch purposes kept separate.
Source reviewed October 14, 2026View supporting excerpt
4553 Walk-In HoursMon–Fri 8:00 a.m. – 5:00 p.m. Call Center & ChatMon–Fri 8:00 a.m. – 4:00 p.m. ContactPhone: (925) 608-9500 Fax: (925) 608-9598 Email: TaxInfo@tax.cccounty.us TTY: Call 711 Home Board & Committee Agendas community warning system Legal terms of use ADA ACCESSIBILITY W
- [4] Contra Costa County — Treasurer-Tax Collector | Contra Costa County, CA Official Website (opens in a new tab)
Contra Costa County · Tax Collector office — specific tax-collection contact block; visitor, mail, telephone and branch purposes kept separate.
Source reviewed October 14, 2026View supporting excerpt
ents or Suggestions? Please let us know by using our on-line response form. Contact Us OfficeFinance Building 625 Court Street, Room 100 Martinez, CA 94553 Mailing AddressContra Costa County Treasurer-Tax Collector P.O. Box 631 Martinez, CA 94553 Walk-In HoursMon–Fri 8:00 a.m. – 5:00 p.m. Call Center & ChatMon–Fri
- [5] Contra Costa County — Treasurer-Tax Collector | Contra Costa County, CA Official Website (opens in a new tab)
Contra Costa County · Tax Collector office — specific tax-collection contact block; visitor, mail, telephone and branch purposes kept separate.
Source reviewed October 14, 2026View supporting excerpt
Martinez, CA 94553 Mailing AddressContra Costa County Treasurer-Tax Collector P.O. Box 631 Martinez, CA 94553 Walk-In HoursMon–Fri 8:00 a.m. – 5:00 p.m. Call Center & ChatMon–Fri 8:00 a.m. – 4:00 p.m. ContactPhone: (925) 608-9500 Fax: (925) 608-9598 Email: TaxInfo@tax.cccounty.us TTY: Call 711 Home Board & Comm
- [6] Contra Costa County — Treasurer-Tax Collector | Contra Costa County, CA Official Website (opens in a new tab)
Contra Costa County · Call center and chat — specific tax-collection contact block; visitor, mail, telephone and branch purposes kept separate.
Source reviewed October 14, 2026View supporting excerpt
sta County Treasurer-Tax Collector P.O. Box 631 Martinez, CA 94553 Walk-In HoursMon–Fri 8:00 a.m. – 5:00 p.m. Call Center & ChatMon–Fri 8:00 a.m. – 4:00 p.m. ContactPhone: (925) 608-9500 Fax: (925) 608-9598 Email: TaxInfo@tax.cccounty.us TTY: Call 711 Home Board & Committee Agendas community warning system Legal ter
- [7] Contra Costa County — business licensing discovery (opens in a new tab)
Contra Costa County official website · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
The County Ordinance requires that you obtain a license for conducting business within the unincorporated areas, even if your business is located outside county limits or you hold a business license from another city.
- [8] Contra Costa County — business licensing discovery (opens in a new tab)
Contra Costa County official website · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
The County Ordinance requires that you obtain a license for conducting business within the unincorporated areas, even if your business is located outside county limits or you hold a business license from another city.
- [9] Contra Costa County — business licensing discovery (opens in a new tab)
Contra Costa County official website · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
The County Ordinance requires that you obtain a license for conducting business within the unincorporated areas, even if your business is located outside county limits or you hold a business license from another city.
- [10] Contra Costa — business-license application instructions (opens in a new tab)
Contra Costa County · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
However, if your business is located in an incorporated city limit and you conduct any business in an unincorporated area of the county, you will need a business license from both the city and the County. If you conduct business only within the city’s limits, you do not need to apply for a County business license.
- [11] Contra Costa — business-license application instructions (opens in a new tab)
Contra Costa County · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
If your business is located in an unincorporated area of the County, you will first need to contact the Department of Conservation and Development at 925-655-2700 or visit them at 30 Muir Road, Martinez, CA 94553, for zoning and planning requirements and permits. Once zoning and planning approval is secured, you may complete the online Business License application and attach the approval notice.
- [12] Contra Costa — business-license application instructions (opens in a new tab)
Contra Costa County · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
If your business is located in an unincorporated area of the County, you will first need to contact the Department of Conservation and Development at 925-655-2700 or visit them at 30 Muir Road, Martinez, CA 94553, for zoning and planning requirements and permits. Once zoning and planning approval is secured, you may complete the online Business License application and attach the approval notice.
- [13] Contra Costa — business-license application instructions (opens in a new tab)
Contra Costa County · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
If your business is located in an unincorporated area of the County, you will first need to contact the Department of Conservation and Development at 925-655-2700 or visit them at 30 Muir Road, Martinez, CA 94553, for zoning and planning requirements and permits. Once zoning and planning approval is secured, you may complete the online Business License application and attach the approval notice.
- [14] Contra Costa County — business licensing discovery (opens in a new tab)
Contra Costa County official website · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
Some businesses may qualify for exemptions (e.g., agriculture or non-profit). An exemption application must be filed annually with the Tax Collector, along with proof of exempt status.
- [15] Contra Costa County — business licensing discovery (opens in a new tab)
Contra Costa County official website · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
To close a license, return your Business License with a written request, or email businfo@tax.cccounty.us.
- [16] Contra Costa County — business licensing discovery (opens in a new tab)
Contra Costa County official website · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
The County Ordinance requires that you obtain a license for conducting business within the unincorporated areas, even if your business is located outside county limits or you hold a business license from another city.
- [17] Contra Costa County — business licensing discovery (opens in a new tab)
Contra Costa County official website · Reviewed business licensing instructions
Source reviewed October 16, 2026View supporting excerpt
To close a license, return your Business License with a written request, or email businfo@tax.cccounty.us.