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Contra Costa County, CA Home Business: Zoning & Home Occupation Permits (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified June 2026

Key Facts

Standards Section
§ 82-40.010
Ministerial Permit Standards
§ 82-40.012
Floor Area Limit
1 room or 20% of floor area, whichever is greater
Employees
Residents only (state-law exceptions aside)
Onsite Clients
Prohibited (except home-instruction: 1 student at a time, ≤6 visits/day, 8am-6pm)
Business Vehicles
1 vehicle, rated ≤1 ton; no limos, dump trucks, tow trucks, construction equipment
Delivery Hours
8:00 a.m. – 8:00 p.m.

Summary

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.

City-specific rules exist: Brentwood, Richmond, San Ramon, Antioch, and Concord have their own zoning & home occupation permits rules that differ from Contra Costa County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

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 the residential use of adjacent properties may be created by the Home Occupation.

Source: Contra Costa Ord. Code Ch. 82-4 (Home Occupations)View official code

Full Breakdown

' Outdoor storage of equipment, parts, materials, supplies, merchandise, refuse or debris is prohibited; hazardous chemicals beyond those normally associated with residential use are also barred. 012 (Ministerial permit) further requires the occupation to be conducted entirely within a residential dwelling unit using no more than one room or 20% of the floor area, whichever is greater, or within an accessory building that meets the principal-structure setbacks. ), and only one business-related vehicle with a rated capacity of up to one ton is allowed (limousines, dump trucks, tow trucks, construction vehicles, trailers, and one-ton+ vehicles are prohibited). and may not exceed the frequency or vehicle types normally associated with residential neighborhoods.

Violations & Fines

Operating a home occupation outside these zoning standards is a violation of Title 8 of the Ordinance Code. Code enforcement may revoke the Home Occupation Permit, require the business to cease, and impose administrative penalties. Persistent violations may be abated as a public nuisance under the County's general code-enforcement authority.

Frequently Asked Questions

How much of my house can I use for a home business?
Under § 82-40.012, no more than one room or 20 percent of the floor area of the dwelling unit (whichever is greater) may be used for the home occupation. You can alternatively use an accessory building if it meets the principal-structure setbacks for your zoning district.
Can I have employees or customers come to my home?
Generally no for the ministerial permit. § 82-40.012 limits the home occupation to residents of the dwelling and prohibits onsite clients or customers, with one narrow exception: individual home instruction (one student at a time, no more than six student visits per day, and only between 8 a.m. and 6 p.m.). Non-resident employees or open client traffic require a discretionary Land Use Permit.
What about deliveries and noise?
§ 82-40.010 caps deliveries at frequencies and vehicle types 'normally associated with residential neighborhoods' and only between 8 a.m. and 8 p.m. The business may not create noise, odor, dust, fumes, vibration, smoke, electrical interference, or any other interference with neighbors' residential use, and may not use water/electricity/sewer beyond normal residential levels.

Sources & Official References

Other rules in Contra Costa County

All Contra Costa County rules

How Contra Costa County compares: Easiest Cities to Run a Home Business·California rules heatmap·Compare Contra Costa County to another location·View the California home business overview

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