Alameda, CA Accessory Structures: ADU Rules (2026)

Alameda adopted ADU/JADU development standards in AMC Section 30-5.18 to implement California's statewide ADU law. Per the City's ADU information packet, a detached ADU of up to 800 sq ft and up to 16 feet in height, with 4-foot side and rear yard setbacks, must be permitted; the total floor area of any ADU cannot exceed 1,200 sq ft. ADUs are reviewed ministerially as part of the building-permit process, with no public notice or hearing required, and state law caps each review round at roughly 30 days. The property-owner-occupancy requirement no longer applies to ADUs (it still applies to JADUs). State law waives parking for ADUs within a half-mile walking distance of public transit. ADUs may not be sold separately from the primary dwelling, and any rental must be for a term longer than 30 days (no short-term/Airbnb use). Because Alameda is a Victorian-era community, historic review can attach: if a garage built before 1942 is to be demolished or converted, a Certificate of Approval application (a discretionary process with neighbor notification) must first be approved by the Planning Division to determine whether the garage is a historic resource.