Contra Costa County, CA Building Setbacks & Zoning: Setback Rules (2026)

Corner lots in unincorporated Contra Costa County have unique setback requirements because they abut two streets. Under Ordinance Code Title 8, Division 84, the primary front setback applies to the side fronting the designated main street of the address, while the street-side yard (the yard facing the secondary street) is subject to a reduced setback, commonly 10 to 15 feet depending on the zone. For example, in R-6, the street-side setback may be 10 feet; in R-10 or R-15, it may be 15 feet. The rear yard on a corner lot is determined by the orientation opposite the front, and the interior side yard follows the standard side-yard rule for the zone. At the intersection itself, a sight-distance (vision) triangle must be kept clear of visual obstructions above 3 feet in height (fences, hedges, walls, signage) to protect driver visibility, typically measured 15-25 feet along each curb line from the corner. Fences in the street-side yard are generally limited to 3.5 to 4 feet in height in the portion that falls within the setback, even though fences along interior side and rear lines can go to 6 feet. Encroachment into the sight triangle is a common enforcement issue. Consult DCD Planning for parcel-specific dimensions.