Sacramento County, CA Accessory Structures: ADU Rules (2026)

Sacramento County regulates accessory dwelling units in unincorporated areas under Section 5.4.5.B of the Zoning Code, implementing California's ADU law (Gov. Code 65852.22 and the 66310-66342 series). A single-family or halfplex parcel may have one ADU plus one JADU. New-construction detached ADUs are capped at 1,200 square feet, while attached ADUs may not exceed 50 percent of the primary dwelling's habitable area or 800 square feet, whichever is greater; the minimum habitable size for either an ADU or JADU is 150 square feet. JADUs are limited to 500 square feet of space within the proposed primary dwelling (including attached garages or storage) plus 150 square feet for ingress/egress. Detached ADUs are limited to 16 feet to the peak (up to 18 feet near a major transit stop or to match the primary roof pitch, and up to 20 feet if set back at least 10 feet from the rear and 5 feet from the side); attached ADUs may reach 25 feet. Setbacks are 20 feet front, 12.5 feet side-street, and 4 feet for side and rear yards. One parking space per ADU is required unless the unit is within one-half mile of transit, in a historic district, part of the existing dwelling, or other listed exemptions. The county also offers free pre-approved 'shelf-ready' detached ADU plans (460, 870, 1,000, and 1,184 sq ft) to unincorporated residents.