Can I Build ADU in Indianapolis, IN? (2026)

Can I build an ADU (carriage house or garage apartment) on my Indianapolis property?

Yes. Indianapolis-Marion County Unified Development Ordinance (UDO) allows accessory dwelling units — commonly called carriage houses or garage apartments — on single-family lots. Detached ADUs up to 900 sqft. No owner-occupancy requirement. No impact fees — permit costs are among the lowest of major US cities. One parking space required per ADU. Alley-access lots in historic neighborhoods like Old Northside and Irvington are particularly well-suited for carriage house ADUs. Permits through Indianapolis DMD.

What is Unigov and how does it affect my permits and zoning?

Unigov is Indianapolis's unique consolidated city-county government structure, established in 1970 by the Unigov Act. It merged Indianapolis city government with Marion County government into a single metropolitan government. For zoning and building permits, this means the Indianapolis Department of Metropolitan Development (DMD) administers the Unified Development Ordinance (UDO) for virtually all of Marion County — not just the old city limits. Most Marion County residents use the same DMD permit office and UDO rules. Exceptions include the excluded cities of Beech Grove, Lawrence, Southport, and the town of Speedway, which have their own local governments.

Are short-term rentals (Airbnb) allowed in Indianapolis?

Yes, without a primary-residence requirement — a significant difference from many cities. Indianapolis requires STR registration ($125/year) with DMD. No nightly cap. Designated local contact required for 24/7 complaint response. Indiana Hotel/Motel Tax (7%) plus Marion County Innkeeper's Tax applies. Insurance minimum of $500,000 required. Indianapolis is a major convention and sporting events city (Colts, Pacers, Indianapolis 500, Big Ten tournaments) — STR demand is strong particularly during major events at Lucas Oil Stadium and Gainbridge Fieldhouse.

What historic districts exist in Indianapolis and what do they require?

Indianapolis has several locally designated historic districts including the Old Northside Historic District (Victorian-era homes northeast of downtown), Lockerbie Square (one of Indianapolis's oldest neighborhoods, brick cottages), Irvington Historic District (late 19th century suburb, National Register listed), and the Meridian Street Preservation District (grand boulevard with mansion-scale homes). The Indianapolis Historic Preservation Commission (IHPC) reviews all exterior alterations in designated areas. Certificate of Appropriateness (CoA) required before DMD issues building permits. Monthly IHPC public hearings at City-County Building.

How does Indianapolis's Indiana Cottage Food Law compare to other states?

Indiana has one of the more generous cottage food laws in the Midwest. The $50,000 annual revenue cap is higher than Ohio ($35,000), Pennsylvania ($35,000), and Michigan (no cap but more restrictions). No state permit or registration required for operations under the cap — just the required product labeling. Indianapolis City Market and Broad Ripple Farmers Market are major venues for cottage food sellers. The law covers baked goods, jams, jellies, candy, dried herbs, and has been expanded to include some refrigerated items sold immediately. Full text at Indiana Code Section 16-42-5.2.

What are the flood risk areas in Indianapolis and how does it affect development?

Indianapolis has significant flood risk areas along the White River, Fall Creek, Eagle Creek, and several smaller creek systems. The White River bisects the city from north to south. Properties in FEMA Special Flood Hazard Areas (Zone AE) require flood insurance and must meet Indianapolis floodplain management standards. New construction in flood zones must have finished floor elevation at least 1 ft above 100-year flood elevation. Indianapolis has invested in flood control after historic flooding events. The Marion County floodplain map and FEMA Flood Map Service Center are the definitive sources for your property's flood zone status.