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Business licenses & tax certificates

Check the local authority, requirements, applications, renewal, changes and public license searches for your business.

Check or apply for a business license Renew a business license Close or update a business license Look up a business license Register a business for stormwater compliance

Before you start

Start with where your business is located and where it will operate. A county license may apply only to unincorporated areas or specific activities; cities can have their own requirements.
Some county offices provide guidance or referrals and do not issue a general business license. Read the entry before choosing an application.
A business license or tax certificate, an FBN/DBA filing, business entity registration and a professional license serve different purposes. Zoning, health and other activity permits may also apply. Business stormwater registration is a separate local programme where required.
Check the license period, renewal date and rules for changes in ownership or location. A renewal may not cover a move or a new owner. Fees and application steps depend on the license category.

1 guide with reviewed service links · Contra Costa

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County government · Contra Costa

Treasurer-Tax Collector

Business licensing

County business-license jurisdiction, activity requirements and exemptionsOfficial instructions

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. Area details & sources

Source checked October 16, 2026

Contra Costa County official website · Contra Costa County — business licensing discovery (opens in a new tab)

Reviewed business licensing instructions

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.

Saved evidence: c1ee49520641bd86 · Agent source review

Apply after the required zoning and planning approvalOfficial online service

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. Area details & sources

Source checked October 16, 2026

Contra Costa County · Contra Costa — business-license application instructions (opens in a new tab)

Reviewed business licensing instructions

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.

Saved evidence: 638f1408e03650b4 · Agent source review

Request closure of an existing county business licenseOfficial instructions

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. Area details & sources

Source checked October 16, 2026

Contra Costa County official website · Contra Costa County — business licensing discovery (opens in a new tab)

Reviewed business licensing instructions

To close a license, return your Business License with a written request, or email businfo@tax.cccounty.us.

Saved evidence: c1ee49520641bd86 · Agent source review

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