Vanderburgh County, IN Accessory Structures: ADU Rental Restrictions (2026)

072 of the Vanderburgh County Code allows an accessory dwelling unit on any lot with a single-family home or duplex as the principal use, but only one ADU per lot, and every dimensional and occupancy rule is built to keep the property functioning as a single household. The ADU must measure between 400 and 800 square feet, or up to 40 percent of the principal structure's floor area (whichever is greater), and the lot must be at least 5,000 square feet. 6 is the rental control: the property owner must occupy either the principal residence or the ADU as a primary residence, sign an affidavit filed with the ADU application, and record a deed or title restriction with the Vanderburgh County Recorder stating that either the principal residence or the ADU will be owner-occupied.

That filing keeps an investor from renting both units to unrelated tenants with no owner on site. 030, so the five-unrelated-person cap applies to the principal home and the ADU combined, not to each structure separately. An ADU also cannot be a shipping container, mobile home, recreational vehicle, other motor vehicle, travel trailer, or boat, and it cannot be sold or divided from the principal use. If the principal structure connects to public water and sewer, the ADU must connect too, with Water and Sewer Utility approval submitted before the Improvement Location Permit issues; a septic-served property instead needs Health Department sign-off. Any existing code violation on the property must be resolved before the county will issue the ADU permit.