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

Santa Cruz County Code Chapter 13.10 (Zoning) governs Accessory Dwelling Units (ADUs) and Junior Accessory Dwelling Units (JADUs). ADUs are allowed on any parcel where the zoning district or General Plan allows residential uses, provided there is an existing or proposed primary dwelling. The Code defines several ADU types: Conversion ADU (conversion of any portion of a legal accessory structure, a single-family dwelling, or a garage, with additions up to 150 sq ft); New Construction ADU; and Junior ADU (residential living area contained within a single-family dwelling, with kitchen and size restrictions). State law (Gov. Code 65852.2 and 65852.22) overrides any local rule that is more restrictive. The California Department of Housing and Community Development reviewed County Ordinance 5382 (adopted 10/19/2021) and found portions of the County's ADU ordinance non-compliant with state law - state default standards apply where the local rule is preempted. Short-term rentals are not allowed on parcels containing an ADU or JADU under state law (Gov. Code 65852.2(a)(6)). In the Coastal Zone, ADU approval may still need a Coastal Development Permit.