Home Business in Contra Costa County, CA (2026)

4 county-level rules, plus city-specific rules for 7 cities in Contra Costa County, California.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Contra Costa County. If you live within an incorporated city, that city's own rules apply: see the city list below.

Zoning & Home Occupation Permits

Home occupations are permitted in every legally established residential dwelling unit in any zoning district of unincorporated Contra Costa County, but only as a use 'incidental and subordinate' to the residence. The business must occupy no more than one room or 20 percent of the floor area (whichever is greater), use only residents as employees, allow no onsite clients except limited home instruction, and create no exterior indication, noise, odor, dust, fumes, vibration, smoke, or other nuisance.

Home occupations allowed in any residential dwelling, with strict standards

Some Restrictions

Contra Costa County Ordinance Code § 82-40.010 (Standards applicable to all Home Occupations); § 82-40.012 (Ministerial permit)

1. Use. The Home Occupation must be incidental and subordinate to the use of the property as a residence. ... 4. Appearance. The residential appearance of the property at which the Home Occupation is conducted must be maintained, with no exterior indication of a Home Occupation. ... 6. Nuisances. No noise, odor, dust, fumes, vibration, smoke, electrical interference, or other interference with ...

Full ordinance details →Official source ↗

Signage Rules

Contra Costa County prohibits all exterior indication of a home occupation in unincorporated areas. Exterior signs, window displays, outdoor displays, and any other outward signs that a business is being conducted from a residence are not allowed; the property must keep its ordinary residential appearance.

No exterior signs or displays for home occupations

Some Restrictions

Contra Costa County Ordinance Code § 82-40.010(4) (Appearance)

Appearance. The residential appearance of the property at which the Home Occupation is conducted must be maintained, with no exterior indication of a Home Occupation. Exterior signs advertising the Home Occupation, window displays, outdoor displays, and other exterior indications of the Home Occupation may not be used.

Full ordinance details →Official source ↗

Customer Traffic Restrictions

Home occupations in unincorporated Contra Costa County generally may not receive customer or client visits at the home. State-licensed family daycare is the protected exception. Violations draw escalating daily citations and can lead to permit revocation.

Home Business: Customer Traffic

Some Restrictions

Contra Costa County Ordinance Code § 82-40.010(3) (Traffic and deliveries); § 82-40.012(C) (Clients or customers); § 82-40.012(D) (Vehicles)

3. Traffic and deliveries. The Home Occupation may not generate vehicular traffic that exceeds the traffic normally associated with a single-family residential use. Deliveries to the Home Occupation may not exceed the frequency of deliveries and types of vehicles normally associated with residential neighborhoods. Deliveries to the Home Occupation may occur only between the hours of eight a.m. ...

Full ordinance details →Official source ↗

Home Daycare

Small family day care homes (up to 8 children) and large family day care homes (up to 14 children) are protected by California Health & Safety Code sections 1597.30-1597.622. Contra Costa County cannot prohibit them in residential zones and must treat them as residential uses for zoning purposes.

Home Business: Day Care Home

Heavy Restrictions

California Health & Safety Code § 1597.45(a)-(e)

(a) The use of a home as a small or large family daycare home shall be considered a residential use of property and a use by right for the purposes of all local ordinances, including, but not limited to, zoning ordinances. (b) A local jurisdiction shall not impose a business license, fee, or tax for the privilege of operating a small or large family daycare home. (c) Use of a home as a small or...

Full ordinance details →Official source ↗