Wayne County, IN Accessory Structures: ADU Rules (2026)

Wayne County Code § 156.004 defines DWELLING UNIT, ACCESSORY or ADU as a detached dwelling on a permanent foundation that is accessory to the main dwelling and commonly used for generational occupancy, then lists development standards with real numbers rather than vague guidance. An ADU cannot exist without a primary single-family dwelling on the property, and only one ADU is permitted per parcel. Separation from the primary dwelling depends on the district: a minimum of 100 feet in the Agricultural and Commercial Districts and on property with a legally non-conforming primary dwelling, or a minimum of 50 feet in the Residential Districts.

The unit itself must have a minimum of 576 square feet of living area, and height is capped at one and one-half stories, except an ADU built above a detached garage, which may rise to 30 feet overall. Parking is a separate requirement: the ADU needs at least one off-street parking space in addition to whatever off-street parking the primary dwelling already requires. Every ADU must also meet all minimum residential code and ordinance requirements for septic, zoning and construction under § 156.004(l), so a septic permit review runs alongside the zoning review.

Because the definition restricts ADUs to districts that permit residential use or carry legal non-conforming residential use, with subdivisions excepted, a lot's underlying zoning classification determines whether an ADU is available there at all before any of the numeric standards come into play.