Martinez, CA Accessory Structures: Carport Rules (2026)

Contra Costa County treats a carport as an accessory structure - a roof or covered area used to shelter vehicles - and regulates it under both the zoning code (Title 8 of the Ordinance Code) and the building code (Title 7). The yard requirements depend on the property's land-use district. In the R-6 Single-Family Residential District (Chapter 84-4), Section 84-4.1004 requires at least a 20-foot front-yard setback for any structure, with corner lots requiring 20 feet on the principal frontage and at least 15 feet on the other street side; the chapter also sets minimum side and rear yards that the carport must meet. R-7, R-10, R-15, R-20, R-40, R-65, and R-100 districts in Chapters 84-6, 84-8, 84-10, 84-12, 84-14, 84-16, and 84-18 set their own progressively larger yard requirements based on lot size. Chapter 82-12 (Setbacks) of Division 82 supplies the general setback definitions and corner-lot rules used across the residential districts. Carports attached to the primary dwelling are generally treated as part of the primary structure for setback purposes, while detached carports are accessory structures subject to accessory-structure standards. Building permits are issued by the Contra Costa County Department of Conservation and Development - Building Inspection Division and require structural plans showing footings, posts, roof framing, and roof load consistent with the California Building Code (Title 24, Part 2) as adopted by the county; carports in special wind, fire, or flood zones must meet additional requirements under Title 7 of the Ordinance Code. Off-street parking must be provided per the underlying zoning district (commonly two covered or off-street spaces per single-family dwelling under Chapter 82-16), and carports are one of the structural forms that can satisfy that requirement. Where the property is also a permitted short-term rental under Chapter 88-32, the STR operating standards require at least one off-street parking space for properties with three or fewer bedrooms and at least two off-street spaces for four or more bedrooms - a carport space counts toward that requirement. ADU rules in Chapter 82-24 allow conversion of an existing garage or carport but require that displaced required parking for the primary dwelling be replaced if the underlying zoning still requires it, consistent with California Government Code Section 65852.2.