Straight answers
Are tiny homes legal in Indiana, and which counties allow them?
Yes on a foundation, wherever the local zoning allows a house that small, and the building code is the same in every Indiana county. The 2020 Indiana Residential Code, 675 IAC 14-4.4, has applied statewide since 26 December 2019. It is the 2018 International Residential Code with Indiana's amendments, and it adopts that code's tiny house appendix, Appendix Q, for dwellings of 400 square feet or less excluding lofts, so the relaxed ceiling, loft and ladder rules are available everywhere in the state. What changes from county to county is set in the code's own table: footing depth of 24, 30 or 36 inches and ground snow load of 20 or 30 pounds per square foot. Whether a lot may hold a small house, or a second home behind the first, is decided by the city or county zoning ordinance. No Indiana law makes a city or county allow a backyard unit, although a 2026 law requires every one to hold a public hearing by 1 January 2027 to review its zoning for more housing, including accessory dwelling units.
Figures verified against the sources below · October 27, 2026
01 — The longer answer
What the state sets in every county, and what your county decides
One residential code for all 92 counties
The Fire Prevention and Building Safety Commission adopts the building rules, and its rules page lists 675 IAC 14-4.4, the 2020 Indiana Residential Code, as currently in effect from 26 December 2019, adopting by reference the 2018 International Residential Code, first printing. Section R101 as Indiana rewrote it applies the code to the construction and prefabrication of detached one- and two-family dwellings, townhouses of up to three stories and their accessory structures. The statute calls these Class 2 structures: a building intended to contain only one or two dwelling units, and its outbuildings (IC 22-12-1-5). A design built to a newer national edition is not automatically compliant, because the Indiana code is the 2018 edition with state amendments.
The tiny house appendix is adopted statewide
The 2020 Indiana Residential Code says provisions in the appendices are not enforceable unless specifically adopted, and the rule then adopts two: Appendix E, for manufactured housing used as dwellings, and Appendix Q, tiny houses, deleting the others it names. Section 675 IAC 14-4.4-242 reads that Appendix Q is adopted and strikes the sentence saying the appendix is not mandatory unless referenced in a local ordinance. So in Indiana the appendix is part of the state code, not a city option. It applies to a tiny house used as a single dwelling unit, defined as 400 square feet or less in floor area excluding lofts, which must otherwise comply with the code.
What Appendix Q relaxes, including Indiana's ladder rule
Habitable space and hallways need a ceiling of at least 6 feet 8 inches, and bathrooms, toilet rooms and kitchens at least 6 feet 4 inches; a loft may be lower. A loft used for sleeping or living needs at least 35 square feet and at least 5 feet in every horizontal direction, and the parts of a sloped loft under 3 feet of height do not count toward that area (under 16 inches below a gable roof of at least 6 in 12). The appendix allows stairs, ladders and other access types to a loft. Indiana rewrote the ladder section: rungs at least 12 inches wide, spaced 10 to 14 inches apart and uniform within 3/8 inch, and each rung able to carry a 300 pound load.
What changes by county: footings, snow, wind and seismic
Indiana replaced the code's climate table with its own, Table R301.2(1), which lists every county. The minimum depth from finished grade to the bottom of a footing is 24 inches in 36 counties, mostly in the south, 30 inches in 29 counties across the middle of the state, including Marion, and 36 inches in 27 northern counties, including Allen, Lake, Elkhart and St. Joseph. Ground snow load is 30 pounds per square foot in 16 northern counties, among them Lake, Porter, LaPorte, St. Joseph, Elkhart and Steuben, and 20 everywhere else. The design wind speed is 115 miles per hour in every county. Fourteen counties in the south and southwest, including Vanderburgh, Posey and Warrick, are in Seismic Design Category C; the rest are A or B. These are the figures a foundation and a roof are designed to, so they belong in the plans before a permit application.
Which counties allow tiny houses: zoning decides, not the code
The building code says how a small house is built in every county; it does not say where one may stand. Minimum house sizes, whether a second dwelling is allowed on a lot, and where a home on wheels may be lived in are set in the local zoning ordinance, which in Indiana is written by each city, town and county. There is no state list of counties that allow tiny houses, and a list that claims to be one is a summary of local ordinances that change. The question to put to the county or city planning office for a specific lot is whether its zoning allows a single-family dwelling of the size you want, and, for a backyard home, whether it allows an accessory dwelling unit.
No statewide right to a backyard home
Indiana has no law that makes a city or county allow an accessory dwelling unit by right. Since 2026 the Indiana Code defines one (IC 36-7-1-1.5): a self-contained living unit inside a single-family house or on the same lot, with its own cooking, sleeping and sanitation facilities, no larger than 75 percent of the house's interior habitable area or 1,000 square feet, whichever is less, and built to the applicable codes. In the 2026 text of Title 36, Article 7, the term is used in that definition and in a list of factors for a zoning review, and no section makes the unit a permitted use. Earlier, House Enrolled Act 1005 of 2025 ranked state infrastructure loans in favour of communities that had voluntarily changed their zoning to allow accessory dwelling units and manufactured and modular housing.
The 2026 zoning review due by 1 January 2027
IC 36-7-4.3-3, added in 2026, requires every county, city and town to hold a public hearing no later than 1 January 2027 to review its unified development ordinance and zoning rules, with the goal of increasing housing. Its listed factors include allowing accessory dwelling units and manufactured and modular housing, and waiving rules such as minimum lot size and square footage, larger setbacks, off-street parking, steeper roof pitch, and design standards that bar code-compliant products. By the same date each unit must send the Legislative Services Agency the hearing minutes and any new or amended ordinance, with a written description of how it changed (IC 36-7-4.3-4). The law requires the review, not any particular result, so check your county's ordinance after its hearing.
Permit deadlines and private plan review
Since 1 January 2026, a city, town or county that requires a permit, plan review or inspection for a house must follow IC 36-7-2.5. It has three business days to say whether an application is complete, and seven business days after that to finish a required plan review. If it said it could review in time and did not, it must issue a permit or a limited permit by the next business day. An applicant may instead use a private provider, a registered architect, a registered engineer or a certified building official, for the plan review or inspections (IC 36-7-2-9.1). A 2026 amendment adds that a unit that misses these deadlines forfeits and refunds its regulatory fees, unless the delay was outside its control or the applicant's fault. The statute applies where the unit requires these steps, so ask the county what it requires for your lot.
Fees after 2026
IC 36-7-2.3, also added in 2026, covers permit, application, inspection and similar fees for residential buildings and for zoning approvals. After 31 December 2026 a unit may not charge more than is reasonably necessary to cover its cost to process the application, review the plans and inspect, and may raise a fee only once every five years by the change in the consumer price index, unless its cost has substantially changed and it holds a public hearing. The money has to sit in a dedicated fund that pays only for those costs.
On wheels, and built in a factory
Indiana law defines a mobile structure as a fabricated unit designed to be towed, with or without a permanent chassis, and connected to utilities for year-round occupancy or use (IC 22-12-1-17), and the 2020 Indiana Residential Code says it does not apply to mobile structures. So the code, and its tiny house appendix, describe a house that is not towable. A building made in whole or substantial part in a factory for installation at the site is an industrialized building system under IC 22-12-1-14, and the commission keeps separate rules for those and for mobile structures in 675 IAC 15. How a particular factory-built unit is approved is a question for the manufacturer, ours included, to answer for your address before you order.
The honest summary is that Indiana is one of the few states where the tiny house appendix is part of the statewide residential code, and its footing and snow figures are printed county by county. What it does not settle is zoning. Whether your lot may hold a small house or a second one behind the first is your county's or city's decision, and every one of them has to put that question to a public hearing by 1 January 2027.
03 — Sources
Each figure above links to the authority it came from.
Fire Prevention and Building Safety Commission rules page: 675 IAC 14-4.4, 2020 Indiana Residential Code, adopting the 2018 International Residential Code, first printing, currently in effect, effective 26 December 2019; 675 IAC 15 rules for industrialized building systems and mobile structures.
in.govFinal rule, LSA Document #19-330(F), adding 675 IAC 14-4.4: Section R101 as amended (scope; appendices not enforceable unless specifically adopted; does not apply to mobile structures as defined in IC 22-12-1-17); Table R301.2(1) climatic and geographic design criteria by county; 675 IAC 14-4.4-230 (Appendix E adopted) and 14-4.4-242 (Appendix Q adopted, its not-mandatory sentence deleted, AQ104.2.2.1 ladder text changed); other appendices deleted.
clarkcounty.in.gov2020 Indiana Residential Code, integrated text, Appendix Q Tiny Houses: AQ101.1 scope, AQ102.1 tiny house defined as a dwelling of 400 square feet or less in floor area excluding lofts, AQ103.1 ceiling heights, AQ104.1 loft area and dimensions.
codes.iccsafe.orgIndiana Code 2026, Title 36, Article 7: IC 36-7-1-1.5 (accessory dwelling unit defined, as added by P.L.73-2026); IC 36-7-2-9.1 (private plan review and inspection where a unit requires a permit, plan review or inspection for a Class 2 structure); IC 36-7-2.3 (fee limit after 31 December 2026); IC 36-7-2.5-16, -17, -21 and -23.5 (application, plan-review and permit deadlines; fee forfeiture); IC 36-7-4.3-3 and -4 (public hearing and report by 1 January 2027).
iga.in.govIndiana Code 2026, Title 22, Article 12: IC 22-12-1-5 (Class 2 structure), IC 22-12-1-14 (industrialized building system), IC 22-12-1-17 (mobile structure).
iga.in.govHouse Enrolled Act 1005 (2025), as enrolled: loan-ranking priority for communities that voluntarily revised zoning to allow accessory dwelling units and manufactured and modular housing (IC 5-1.2-15.5-14); IC 36-7-2.5 Class 2 structure building permits, effective 1 January 2026.
iga.in.gov
04 — Related questions
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