Santa Cruz County, CA Accessory Structures: ADU Rules (2026)

Santa Cruz County regulates ADUs in its unincorporated areas under County Code Section 13.10.681, implemented consistent with California's ADU law (Gov. Code 66310-66342), which preempts overly restrictive local rules. The County's published ADU/JADU Development Standards set a minimum unit size of 150 sq ft. Detached ADUs may be up to 850 sq ft (studio/1-bedroom) or 1,000 sq ft (2+ bedrooms) on parcels under one acre, and up to 1,200 sq ft on parcels of one acre or more. Conversion ADUs (within existing space) and junior ADUs (JADUs, 150-500 sq ft) are also allowed. In single-family zones the County permits up to four ADUs total on a lot, combining the state-mandated combinations under Gov. Code 66323. Side and rear setbacks for new construction are 4 feet; detached ADUs inside the Urban Services Line are limited to 16 feet in height (24 feet over a garage). One parking space is generally required for new-construction ADUs, with exemptions near transit, on historic sites, or near car-share. JADUs require owner-occupancy of the property; standard ADUs do not. ADUs cannot be used as short-term rentals (30-day minimum lease). In the Coastal Zone additional building-permit review may apply, and designated coastal areas (such as Live Oak and Seacliff/Aptos/La Selva) require one parking space with no exemptions and replacement parking when existing spaces are removed.