Phoenix, AZ Accessory Structures: Garage Conversions (2026)

Per the City of Phoenix Accessory Dwelling Unit (ADU) Guide and Zoning Ordinance Section 706.A, a garage or carport may be converted into an attached or detached ADU. State law (A.R.S. Section 9-461.18.B) prohibits the city from requiring additional parking solely to accommodate an ADU; however, when an existing garage or carport that provided required parking is converted, equivalent replacement off-street parking spaces must be created elsewhere on the lot in dustproof conditions and must not be located in the front-yard setback. The converted ADU is subject to the same Section 706.A size limit (75 percent of the primary dwelling's gross floor area, capped at 1,000 sq ft on lots up to 10,000 sq ft) and design guidelines, and a detached ADU may sit 5 feet from a street side line and 3 feet from an interior side or rear line. Garage/carport construction or conversion requires a construction permit; applicants submit two sets of building plans with a Construction Permit/Plan Review Application to the residential permit counter.