A tiny house on a permanent foundation is generally treated as an accessory dwelling unit and is allowed wherever ADUs are allowed. A tiny house on wheels is usually classified as a recreational vehicle under 24 CFR 3282.15 and is rarely a permanent backyard dwelling. Whether your state mandates ADUs varies widely by state.
Last verified: September 25, 2026 against 24 CFR 3282.15 via Cornell LII, the HUD Federal Register notice on the RV exemption, IRC Appendix Q, California HCD ADU guidance, and the individual state statutes and state-agency pages cited in the table below.
An accessory dwelling unit, or ADU, is a second, smaller home on a lot that already has a house. Whether you can legally put a tiny house in your backyard depends on two things: how the tiny house is built and classified, and whether your state and local government allow an ADU on your lot. This page explains that distinction, then gives a 50 state plus DC table and an FAQ.
A statewide ADU law tells you whether zoning must let you place a second small home on your lot. A building code such as IRC Appendix Q tells you how a small home may be built. Those are different questions, and a state can have one without the other.
Foundation tiny house versus tiny house on wheels: the key distinction
This is the single most important thing to understand, and it is where most confusion comes from.
A tiny house on a permanent foundation is generally an ADU
A tiny house built on a permanent foundation, connected to utilities, and constructed to the residential building code is generally treated like any other small dwelling. Where a jurisdiction allows accessory dwelling units, a foundation tiny house can usually qualify as one. This is the reliable, defensible path to a legal backyard tiny home. For the foundation ADU rules in the most developed state framework, see the California ADU law and permits pillar.
A tiny house on wheels (THOW) is usually an RV and is much more restricted
A tiny house on wheels, also called a THOW, movable tiny house, or park model RV, is usually classified as a recreational vehicle, not a permanent dwelling. That classification is grounded in federal law. HUD’s regulation defines a recreational vehicle as “a vehicle or vehicular structure not certified as a manufactured home, designed only for recreational use and not as a primary residence or for permanent occupancy,” built and certified to NFPA 1192 or ANSI A119.5 (24 CFR 3282.15).
HUD applies a size and use test for that RV exemption. A unit is treated as an RV, and therefore not a HUD code manufactured home, if it is built on a single chassis, is 400 square feet or less, is self propelled or permanently towable by a light duty truck, and is “designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use” (HUD Federal Register notice, 2018).
Because a THOW or park model is built to ANSI A119.5 or NFPA 1192 (RV standards) rather than to HUD code or the residential building code, most zoning ordinances will not let it be a permanent, year round backyard residence. Legal placement is typically limited to RV parks, mobile home parks, tiny house communities, or campgrounds, often with a seasonal occupancy cap.
Places that carve out a path for movable tiny houses
Some places have built a legal bridge. California is the leading example. Its state housing agency (HCD) states that “moveable tiny homes may be more akin to recreational vehicles, as defined in the California Health and Safety Code section 18010, than ADUs,” and that they “may not meet the statutory definition of an ADU,” while leaving the door open for local ordinances. Cities such as Los Angeles and San Jose have passed movable tiny house ordinances that permit a DMV registered, ANSI certified THOW as an ADU when it meets specific criteria. Washington goes further: its statute itself references a “tiny house with wheels” that can count as an ADU (RCW 36.70A.681). Boise, Idaho adopted a THOW as ADU ordinance effective July 1, 2025. Outside such specific carve outs, treat a THOW as an RV and verify with your city.
The takeaway: if you want a permanent backyard tiny home, a foundation built unit that qualifies as an ADU is the reliable route. A tiny house on wheels as a permanent residence is the exception, not the rule, and depends on a specific local ordinance.
What is IRC Appendix Q (Tiny Houses)?
IRC Appendix Q is an optional appendix to the International Residential Code (IRC). It creates building safety standards tailored to tiny houses and defines a tiny house as “a dwelling that is 400 square feet (37 m2) or less in floor area excluding lofts.”
Key points:
- Appendix Q sets construction standards (ceiling heights, lofts, stairs and ladders, emergency egress) for small homes on a foundation. It makes a small home easier to build legally.
- It is not automatically in force. Code appendices must be separately adopted. Some states adopt Appendix Q statewide; others leave it to each city or county.
- States reported to have adopted Appendix Q statewide as a building code include California, Indiana, Florida, Georgia, Minnesota, Kentucky, Louisiana, Massachusetts, Montana, New Jersey, New York, Utah, Washington, South Carolina, and Tennessee, with dates varying by IRC edition (secondary source; confirm against each state’s adopted code edition).
- Critical caveat: adopting Appendix Q does not force any town to zone for ADUs. It tells you how to build a small home, not whether zoning lets you place one in your backyard. New York and New Jersey, for example, have Appendix Q statewide but no statewide ADU zoning mandate.
Which states let you put a tiny house in your backyard? A 50 state plus DC table
How to read the columns:
- Foundation tiny house allowed as an ADU? “Yes statewide” means the state has a law that requires local governments to allow ADUs in residential zones. “Local zoning, verify with city” means we could not confirm a statewide mandate and you should check local code. “Restricted” means a nominal statewide right is heavily undercut by opt outs or conditions.
- Tiny house on wheels as a permanent dwelling? In almost every state a THOW is an RV and is not a permanent backyard dwelling by right; it is a local zoning question. “By right” means the use is allowed without a special permit or discretionary approval.
- Several statewide ADU laws are newly enacted or phase in on a future date. Those are flagged with their effective date. Do not treat a future effective law as already in force.
| State | Foundation tiny house allowed as an ADU? | Tiny house on wheels as a permanent dwelling? | Key rule or source |
|---|---|---|---|
| Alabama | Local zoning, verify with city | No by right; RV (ANSI A119.5), usually RV parks only | No statewide ADU mandate; 2021 IRC enforced locally (source) |
| Alaska | Local zoning, verify with city | Local only; verify with city or borough | No statewide ADU law; Anchorage adopted permissive ADU reforms 2023 (source) |
| Arizona | Yes statewide (cities over 75,000 only; eff. Jan 1, 2025) | Not addressed by right; verify with city | HB 2720 (2024); large municipalities must allow 1 attached plus 1 detached ADU (source) |
| Arkansas | Yes statewide (eff. Aug 5, 2025) | No by right; must be a code dwelling, not an RV | Act 313 of 2025, Ark. Code Ann. 14-56-205 (source) |
| California | Yes statewide | Not an ADU by state law (treated like RV); allowed only where a local movable tiny house ordinance permits it | State ADU Law, Gov. Code 66310 to 66342 (reorganized by SB 477, 2024) (source) |
| Colorado | Yes statewide (MPO-area jurisdictions; eff. June 30, 2025) | Turns on local rules; verify with city | HB24-1152 (2024) (source) |
| Connecticut | Restricted (statewide by default under PA 21-29, but many towns opted out); verify with town | No by right; must meet building code on foundation; verify with town | Public Act 21-29 (HB 6107), amending C.G.S. 8-1a and 8-2 (source) |
| Delaware | Local zoning, verify with city | No by right; verify with county | Statewide ADU bill in progress; status unverified (source) |
| District of Columbia | Yes (matter of right in most residential zones) | No; must be a fixed structure | 2016 Zoning Regulations (11 DCMR) (source) |
| Florida | Local zoning, verify with city | No by right; RV (Fla. Stat. 320.01), usually RV parks only. Appendix Q adopted statewide | Fla. Stat. 163.31771 (“A local government may adopt an ordinance to allow” ADUs) (source) |
| Georgia | Local zoning, verify with city | No by right; RV or park model. Appendix Q must be adopted locally | No statewide ADU mandate (source) |
| Hawaii | Yes statewide (counties must comply by Dec 31, 2026) | Not addressed by right; ohana unit is family only; verify with county | SB 3202 (2024), Act 39 (source) |
| Idaho | Yes statewide (cities over 10,000; eff. July 1, 2026) | Boise allows THOW as ADU (eff. July 1, 2025); elsewhere local | SB 1354 (2026). Idaho Code 55-3212 is HOA only, not a zoning mandate (source) |
| Illinois | Local zoning, verify with city | No by right; RV, local zoning. Chicago allows ADUs by ordinance | No statewide ADU law (HB 1813 not enacted) (source) |
| Indiana | Local zoning, verify with city | No by right; RV, local zoning. Appendix Q adopted statewide (2019) | No statewide ADU zoning mandate (source) |
| Iowa | Yes statewide (eff. July 1, 2025) | No automatic; must meet building code (Iowa Code ch. 103A) | SF 592 (2025), amending Iowa Code 331.301 and 364.3 (source) |
| Kansas | Local zoning, verify with city | No; treated as temporary or RV, campground use in many areas; verify with city | No statewide ADU law (source) |
| Kentucky | Local zoning, verify with city | No by right; RV. Foundation tiny house under KY Residential Code plus Appendix Q (statewide) | No statewide ADU mandate (source) |
| Louisiana | Local zoning, verify with city | No by right; RV or park model; verify with parish or city | No uniform statewide ADU law (home rule) (source) |
| Maine | Yes statewide (phased in through July 1, 2024) | No by right unless on foundation per MUBEC; verify with city | 30-A M.R.S. 4364-B (ADU) and 4363 (tiny homes) (source) |
| Maryland | Yes statewide (eff. Oct 1, 2025; localities to adopt by Oct 1, 2026) | No by right; RV; verify with city | SB 891 / Ch. 196 (2025) (confirm chapter number before hard cite) (source) |
| Massachusetts | Yes statewide (eff. Feb 2, 2025) | No by right; RV or park model, camping use; must meet building code | Affordable Homes Act, Ch. 150 of Acts of 2024, sec. 8; M.G.L. c. 40A sec. 3 (source) |
| Michigan | Local zoning, verify with city | No by right; RV, local zoning | Michigan Zoning Enabling Act, Act 110 of 2006 (delegates zoning to localities) (source) |
| Minnesota | Local zoning, verify with city | No by right; RV, local zoning. Minneapolis and St. Paul allow ADUs locally | SF 3418 (2025) introduced only, not law (source) |
| Mississippi | Local zoning, verify with city | No by right; RV, usually RV parks; verify with city | Miss. Code Ann. 17-2-3 (discretionary statewide minimum codes) (source) |
| Missouri | Local zoning, verify with city | No by right; RV, local zoning. St. Louis allows ADUs (Board Bill 43) | No statewide ADU preemption (source) |
| Montana | Yes statewide (eff. Jan 1, 2024) | Depends on local ordinance; verify with city | Mont. Code Ann. 76-2-345 (SB 528, 2023) (source) |
| Nebraska | Local zoning, verify with city | No by right; RV, local zoning | Neb. Rev. Stat. 19-5501 to 19-5507 (Missing Middle Housing Act; duplex mandate for larger cities) (source) |
| Nevada | Yes statewide (larger cities and counties; eff. July 1, 2026) | Not addressed by right; verify with city | AB 396 (2025), new section of NRS Ch. 278 (source) |
| New Hampshire | Yes statewide (original 2017; strengthened eff. July 1, 2025) | No by right; RV. Foundation ADU allowed | RSA 674:71 to 674:73 (source) |
| New Jersey | Local zoning, verify with city | No by right; RV. Appendix Q adopted statewide (Sept 3, 2019) | No statewide ADU zoning mandate (source) |
| New Mexico | Local zoning, verify with city | No by right; RV, local zoning | No statewide ADU law (HB 425 died in committee; not law) (source) |
| New York | Local zoning, verify with city | No by right; RV. Appendix Q in 2020 Residential Code | No statewide ADU zoning mandate (source) |
| North Carolina | Local zoning, verify with city | No by right; RVIA units are RVs; foundation tiny house OK as single family dwelling | No statewide ADU mandate (HB 409 died; do not cite it as law) (source) |
| North Dakota | Local zoning, verify with city | No by right; RV, local zoning; verify with city | No statewide ADU statute (source) |
| Ohio | Local zoning, verify with city | No by right; RV, local zoning. Cincinnati and Dayton allow ADUs | No statewide ADU statute (zoning under ORC Title 7) (source) |
| Oklahoma | Local zoning, verify with city | No by right; RV, RV park placement; verify with city | No statewide ADU mandate (source) |
| Oregon | Yes statewide | Generally an RV or park model; local option; verify with city (Portland treats THOWs as occupied RVs) | SB 1051 (2017); HB 2001 (2019) (source) |
| Pennsylvania | Local zoning, verify with city | No by right; vehicle under PA Vehicle Code; verify with city | No enacted statewide ADU law (HB 2186 passed House only) (source) |
| Rhode Island | Yes statewide (conditional; eff. June 24, 2024) | No by right; foundation required; ADUs barred from tourist or transient rental | R.I. Gen. Laws 45-24-73 (by right only if one of three conditions met) (source) |
| South Carolina | Local zoning, verify with city | No by right; RV or park model, seasonal (often 180 day limit). Appendix AQ statewide | No statewide ADU mandate (source) |
| South Dakota | Local zoning, verify with city | No by right; RV; verify with city | No statewide ADU statute (source) |
| Tennessee | Local zoning, verify with city | No by right; RV. Foundation tiny house under adopted IRC plus Appendix Q; verify with county | No enacted statewide ADU mandate (HB 2031 in subcommittee) (source) |
| Texas | Local zoning, verify with city | No by default; RV titled with TxDMV, RV park zones; verify with city | No statewide ADU law (SB 673 / HB 2480 did not pass) (source) |
| Utah | Yes statewide (internal ADUs only; eff. Oct 1, 2021) | No by right; detached backyard units remain local option | Utah Code 10-9a-530 (HB 82, 2021) (source) |
| Vermont | Yes statewide (one attached or internal ADU by right; eff. July 1, 2023) | No by right; detached ADUs subject to local review; foundation required | HOME Act / Act 47 (2023), amending 24 V.S.A. 4412 (source) |
| Virginia | Yes statewide (eff. July 1, 2027) | No by right; RV; verify with city | Va. Code 15.2-2292.4 (SB 531, 2026) (source) |
| Washington | Yes statewide | Most permissive: statute references a “tiny house with wheels” that can count as an ADU | EHB 1337 (2023), RCW 36.70A.681 (source) |
| West Virginia | Local zoning, verify with city | No by right; RV, local zoning | No statewide ADU law; IRC statewide construction standard (source) |
| Wisconsin | Local zoning, verify with city | No by right; RV, local zoning. Uniform Dwelling Code governs foundation build | No statewide ADU mandate (AB 365 not enacted) (source) |
| Wyoming | Local zoning, verify with city | No by right; RV, local zoning; verify with city | No statewide ADU statute (source) |
Verification and hedging notes
- Statewide ADU laws confirmed against primary sources (statute or official state agency): California, Oregon, Washington, Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Montana, Colorado, Utah (internal ADUs only), Arkansas, Iowa, Virginia, Maryland, and DC. Arizona (large cities), Nevada, Hawaii, and Idaho are confirmed but future effective or threshold limited.
- Common online errors we corrected: North Carolina HB 409 did not take effect (it stalled in committee); New Mexico HB 425 died and is not law; Idaho Code 55-3212 is an HOA only provision, not a statewide zoning mandate; Minnesota SF 3418 is a pending bill, not law.
- For tiny houses on wheels as a permanent dwelling, with narrow exceptions (California local ordinances, Washington statute, Boise), this is a local zoning matter that we could not pin to a statewide statute. Treat every “no by right” THOW note as “verify with your city or county.”
What changed in 2026, and what changes in 2027?
Several statewide ADU laws took effect in 2025 and 2026, and a few phase in later. The dated milestones from the table above:
- Arizona: HB 2720 took effect January 1, 2025 for cities over 75,000.
- Nevada: AB 396 takes effect July 1, 2026 for larger cities and counties.
- Idaho: SB 1354 takes effect July 1, 2026 for cities over 10,000, and Boise’s THOW as ADU ordinance took effect July 1, 2025.
- Hawaii: counties must comply with SB 3202 (Act 39) by December 31, 2026.
- Virginia: Va. Code 15.2-2292.4 (SB 531) takes effect July 1, 2027.
No further nationwide changes to how tiny houses on wheels are classified are scheduled as of September 25, 2026: the federal RV definition at 24 CFR 3282.15 remains the baseline. We recheck each state legislature and will update this page as new ADU laws are chaptered.
How this connects to the state law pages
Rules differ sharply by state, so start with your own. See California for the most developed foundation ADU framework and its movable tiny house guidance, Washington for the only statute that expressly lets a tiny house with wheels count as an ADU, Massachusetts for its 2025 statewide ADU law, and Maine for its phased ADU and tiny home statutes. For every state we track, browse the ADU laws library.
Frequently Asked Questions
Can I live in a tiny house on my own land?
Sometimes. A tiny house on a permanent foundation, built to the residential code and permitted as a dwelling or ADU, can usually be a legal full time home where zoning allows it. A tiny house on wheels is usually classified as an RV and is generally not allowed as a permanent residence outside RV parks or specific tiny house zones. Check your local zoning first.
Is a tiny house on wheels legal in a backyard?
Usually not as a permanent dwelling. Federal rules classify a tiny house on wheels as a recreational vehicle “designed only for recreational use and not as a primary residence or for permanent occupancy” (24 CFR 3282.15). A few places, for example certain California cities and Washington state, allow a movable tiny house as an ADU under specific rules. Everywhere else, verify locally.
Do I need a permit for a tiny house in my backyard?
Almost always yes. A foundation tiny house needs building permits and must meet the residential code, and IRC Appendix Q where it is adopted. An ADU typically also needs zoning approval. A tiny house on wheels may instead need RV registration or titling. Skipping permits risks fines and removal orders.
What is the difference between a tiny house on a foundation and one on wheels?
A foundation tiny house is built like a small home to the residential building code and is treated as real property, so it can qualify as an ADU. A tiny house on wheels is built to RV standards (ANSI A119.5 or NFPA 1192), is titled like a vehicle, and is treated as an RV, which sharply limits where it can be a permanent home.
Does my state allow ADUs statewide, or is it up to my city?
It varies. States including California, Oregon, Washington, Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Montana, Colorado, Utah, Arkansas, Iowa, Maryland, and Virginia, plus DC, have statewide ADU laws, though several phase in on future dates or apply only to larger cities. Most other states leave ADUs to local zoning. Check the state table above.
What is IRC Appendix Q and does it make my tiny house legal?
Appendix Q is an optional part of the International Residential Code that sets safety standards for tiny houses of 400 square feet or less on a foundation. It makes a small home easier to build legally where it is adopted, but it is a building code, not a zoning law. It does not by itself give you the right to place an ADU on your lot.
How big can a backyard tiny house or ADU be?
Size caps are set by state and local law and vary widely. Appendix Q defines a tiny house as 400 square feet or less. Many ADU laws cap units at 750, 900, or 1,000 square feet, or a percentage of the main home. Check your jurisdiction’s specific limit.
Can I rent out a tiny house ADU in my backyard?
Often yes for long term rental, but not always for short term. Many statewide ADU laws bar owner occupancy requirements, which helps renting. But some laws restrict short term or transient rentals. Rhode Island, for example, prohibits ADUs from being offered for tourist or transient use. Confirm your local rules before renting.
Sources
- 24 CFR 3282.15, recreational vehicle definition (Cornell LII): https://www.law.cornell.edu/cfr/text/24/3282.15
- HUD RV exemption criteria (Federal Register, 2018): https://www.federalregister.gov/documents/2018/11/16/2018-24950/manufactured-home-procedural-and-enforcement-regulations-clarifying-the-exemption-for-manufacture-of
- California HCD, Accessory Dwelling Units (movable tiny homes guidance): https://www.hcd.ca.gov/building-standards/adu
- IRC Appendix Q text (state edition example): https://up.codes/viewer/south_carolina/irc-2021/chapter/AQ/tiny-houses
- Appendix Q state by state adoption (secondary, verify per state): https://tinyhomeindustryassociation.org/appendix-q-state-by-state/
- Individual state statutes and agency pages: see the Source column in the table above.
Disclaimer
This page is general information, not legal advice. Tiny house and ADU rules change often, and local zoning controls the final answer. Confirm the current rules with your local planning department before you build.
Related ADU laws
Other laws and rules in the same silo, kept in step as each one goes live.