Boone County, IN Accessory Structures: ADU Owner Occupancy (2026)

Section 157.063 lets a Boone County property owner add an accessory residential structure to a parcel with an existing primary home, to house family members, students, aging relatives, in-home caregivers or others, and to give owners extra income. The ownership and occupancy standard in the Section 157.063(C) development-standards table ties that flexibility to a strict condition: the accessory dwelling must be under the same ownership as the primary dwelling, it may not be parceled off separately, and the owner of the parcel must actually occupy either the primary or the accessory unit.

That sits alongside the table's other limits, capping the unit at one per parcel, 400 square feet minimum, and requiring it to comply with all applicable building code requirements for a single-family dwelling. Section 157.063(B) also requires anyone with a qualifying accessory structure, one with a bathroom, kitchen or living area, to either meet these standards or file a recorded 'use affidavit' with the Administrator stating it will not be used as an accessory dwelling. A special exception and a separate building permit, plus deed restrictions recorded to keep the standards in effect in perpetuity, are required under Section 157.063(D).