Indianapolis, IN Accessory Structures: ADU Rules (2026)

Accessory dwelling units in Indianapolis are governed by the Indianapolis-Marion County Consolidated Zoning Ordinance (the IndyRezone UDO), Chapter 743, Article III, Section 06 (Accessory and Temporary Uses), subsection 743-306-EE (Secondary Dwelling Unit). A 'Secondary Dwelling Unit' is defined as a dwelling unit that is subordinate and accessory to a single-family detached dwelling. to fit over a 24-foot by 30-foot garage). A dwelling unit owner must occupy either the primary dwelling unit or the secondary dwelling unit on the lot as their permanent residence, meaning both units cannot be rented out simultaneously.

A detached secondary dwelling unit counts toward the total allowable square footage allocated for accessory buildings unless it is constructed above an existing detached accessory building, and within the Compact Context Area a secondary dwelling unit may only be separate from the primary building when located within a permitted accessory building. One additional off-street parking space must be provided, and the unit must have a separate entrance from the primary dwelling unit. For units within or attached to the primary dwelling, the separate entrance must be on a different side of the building or distinguished by a change in materials or plane of at least 3 feet on the same side; for detached units, the entrance must be visible from a right-of-way.

Indiana follows a local-control framework under IC 36-7-4, leaving ADU size, setbacks, and height to the local Indianapolis ordinance rather than preempting them at the state level.