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

Chapter 82-4 of the Contra Costa County Ordinance Code defines and regulates home occupations. A home occupation is permitted as an accessory use in any residential zone if it meets these conditions: (1) conducted entirely within the dwelling or an attached garage; (2) clearly incidental and secondary to the residential use (no more than 25% of the dwelling floor area); (3) no alteration of the residential appearance of the dwelling; (4) no customer or client visits, except as specifically permitted (typically none); (5) no non-resident employees working on-site; (6) no outdoor storage of materials or equipment; (7) no advertising signs on the premises; (8) no increase in pedestrian or vehicular traffic; (9) no generation of noise, vibration, odor, dust, smoke, glare, fumes, or electrical interference detectable off the property. A Home Occupation Permit application is submitted to the Department of Conservation and Development with a small fee; most are approved ministerially. Cottage food operations (jams, baked goods, candies registered under AB 1616) are allowed with Class A or Class B CFO registration through the county Environmental Health Division. Microenterprise home kitchen operations (MEHKOs under AB 626) are allowed in Contra Costa since the county opted in. A California seller's permit and county business license are required for most for-profit home businesses.