Orange County, CA Accessory Structures: Garage Conversions (2026)

Converting a garage into living space in unincorporated Orange County is most commonly done as an accessory dwelling unit (ADU) under Comprehensive Zoning Code Sec. 7-9-90, which conforms to California Government Code Section 65852.2 (recodified as Gov. Code 66310-66342). The code allows an existing detached accessory structure -- including a detached garage, workshop, or storage building -- to be converted to an ADU. A converted ADU may not exceed the square footage of the structure being converted, up to the 1,200 sq ft maximum, and may add up to 150 sq ft beyond the existing footprint solely to accommodate ingress and egress. A key state-mandated benefit appears in Sec. 7-9-90(d)(3): no replacement of removed parking spaces is required when an existing garage, carport, or covered parking structure is converted to an ADU or is demolished to make room for one. JADUs created within a garage that is attached to the home still require replacement parking per the County's ADU fact sheet. Converted units must have direct exterior access, comply with all applicable building codes, and demonstrate adequate water and sewer service. As with all ADUs, the converted unit may be rented only for 30 days or more and cannot be used as a short-term rental. Converting a garage to non-ADU habitable space (such as an extra bedroom) is treated under standard zoning and building permit requirements rather than the streamlined ADU process.