Oro Valley, AZ Accessory Structures: ADU Rules (2026)

The Oro Valley Zoning Code permits accessory dwelling units, commonly called guest houses or casitas, in residential zoning districts subject to specific development standards. The ADU must be located on the same lot as the primary dwelling and be subordinate in size, typically limited to a maximum of 50 percent of the primary dwelling floor area or 1,000 square feet, whichever is less. The property owner must occupy either the primary dwelling or the ADU. The ADU must meet all setback requirements for the underlying zoning district, which may be greater than the setbacks for detached accessory structures. A separate entrance is required so the unit can function independently, but the address must be associated with the primary dwelling parcel. The ADU must connect to the same water and sewer services as the primary dwelling. A building permit is required for new ADU construction or conversion of existing structures (such as a garage or casita) into an ADU. The Town reviews ADU applications through the standard building permit process unless a conditional use permit is required for the specific zone. Parking requirements typically include one additional off-street space for the ADU. ADUs may not be sold separately from the primary dwelling. Short-term rental use of ADUs is subject to the Town's short-term rental regulations and Arizona state law. ARS 33-1816 protects homeowners' rights to install solar panels on ADU roofs despite HOA restrictions.