Contra Costa County, CA Home Business: Zoning Restrictions (2026)

Per Contra Costa County Ordinance Code § 82-40.010 (Standards applicable to all Home Occupations), the Home Occupation 'must be incidental and subordinate to the use of the property as a residence,' may not occupy a required off-street parking space (except that one space may be occupied by a single business-related vehicle), may not generate vehicular traffic exceeding that of a single-family residence, and may not produce 'noise, odor, dust, fumes, vibration, smoke, electrical interference, or other interference with the residential use of adjacent properties.' 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. Section 82-40.012 (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. Only residents of the dwelling may be involved (except as state law otherwise provides), no clients or customers are permitted onsite (except students in individual home instruction — one at a time, no more than six visits per day, only between 8 a.m. and 6 p.m.), 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). Deliveries are restricted to the hours of 8 a.m. to 8 p.m. and may not exceed the frequency or vehicle types normally associated with residential neighborhoods.