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Sandstone bluffs at Garden of the Gods in the Shawnee National Forest of southern Illinois.

Tiny Homes in Illinois: Laws, Rules and Communities

Updated November 4, 2026. Some laws may have changed since then. Confirm with your city or county before you buy land or a home.

The short answer

Yes, you can live in a tiny home full time in Illinois, on a permanent foundation and where local zoning allows it. Illinois has no single residential code that every town must use, but since January 1, 2025, every city and county building code must meet a structural floor based on the International Residential Code. A tiny home on wheels built as an RV or park model is closest to the state's recreational vehicle definitions, though those definitions describe vehicles for recreation or temporary living, and your city or county decides where you can live in one. Chicago opened backyard and basement units to more of the city on April 1, 2026, though Illinois still has no statewide ADU law. The state septic code approves composting toilets certified to NSF/ANSI Standard 41. Illinois has the 24th lowest cost of living of the 50 states, a flat 4.95 percent income tax, an effective property tax rate of 1.88 percent (2nd highest), and homeowners insurance averaging $3,240 a year.

On this page. Quick facts, the rules in plain words, where to start, living in Illinois, communities and common questions.

In Illinois, local governments make most of the rules. Your city, village or county sets zoning and adopts its own building code, and the state sets a floor under that code, a statewide energy code and plumbing code, and the septic rules. A tiny home on a permanent foundation, anchored to a base built into the ground, is a house wherever local zoning allows a home that size. A tiny home on wheels, built on a trailer so it can be towed, has no category of its own in state law that we could find.

This guide covers the building code and the 2025 floor, homes on wheels and titles, manufactured and modular homes, ADUs and the bills that stalled, septic and composting toilets, floodplains, and where to find a place to live small.

Quick facts

  • On a foundation (anchored to a base in the ground): a house, built to whatever code your city or county has adopted.
  • Building code: set locally. Since January 1, 2025, every local building code must regulate a home's structure at least as strictly as the least strict International Residential Code edition published in the current year or the 9 years before it. Where a place has no residential code, a builder's contract for a new home must name one, or the law fills one in.
  • Tiny house appendix (Appendix Q): not adopted statewide. A city or county can adopt it locally, as Yorkville did in 2019.
  • On wheels (built on a trailer): one built as an RV or park model is closest to the state's RV definitions, and one on a homemade trailer is titled as a homemade trailer. We found no state law that allows or bans living full time in one. Local zoning decides.
  • ADUs (a second, smaller home on the same lot as a house): no statewide law. Chicago allows them in eligible areas.
  • Septic (an underground system that treats wastewater where there is no city sewer): plan approval from the state health department or your local health department before you build. Composting toilets certified to NSF/ANSI Standard 41 are an approved method.

Can you live in a tiny home full time in Illinois?

Yes, on a permanent foundation where local zoning allows it. On wheels, it depends on your city or county.

  • On a foundation, a tiny home is a house. It has to meet the building code your city or county uses, the state energy and plumbing codes, and it needs sewer or an approved septic system.
  • Your city or county zoning decides the minimum house size, if there is one. We found no statewide minimum.
  • On wheels, we found no state law that allows or bans living full time in one. Local zoning decides.

The rules in plain words

Building code

Illinois does not have one residential code that every town must use. Cities, villages and counties adopt their own. A 2023 law, Public Act 103-510, set a floor under those codes. Since January 1, 2025, any city or county building code must regulate the structure of a home "at least as stringent as the baseline residential code," which the law defines as the International Residential Code edition, published in the current year or the 9 years before it, with the least restrictive structural rules. The law covers home rule cities and counties too. Cities and counties must also report the code they adopt to the Capital Development Board.

Some places have adopted no residential code at all, and the law treats a place that has not reported its code to the Capital Development Board the same way. There, a state law (815 ILCS 670) says the contract to build a new home must name a code the builder and buyer agree to, either the International Residential Code or a city or county code in effect within 100 miles. If the contract names none, the state energy code, the state plumbing code and the current International Residential Code become part of the contract by law.

That second rule is not settled for every buyer. The law is written around a contract between a home builder and a home purchaser, and it defines a home builder as someone who builds a home for sale or for another person's use and expects to profit from it. It says nothing directly about an owner who builds a home for themselves, though that definition suggests the rule does not reach an owner-builder. If you plan to build your own tiny home where there is no local code, ask the county what it expects, and keep in mind that the state energy and plumbing codes apply to all homes either way.

The state energy code applies to the construction of, renovations to and additions to all homes in Illinois, and the law lets a few places set stricter energy rules. The state plumbing code and fire safety rules apply too.

The tiny house appendix

The national code has an optional appendix for homes of 400 square feet or less, often called Appendix Q. It eases ceiling heights and allows smaller lofts. Illinois has not adopted it statewide, and the 2025 floor does not add it. A city or county can adopt it on its own. Yorkville adopted the 2018 International Residential Code with Appendix Q, effective January 1, 2020. Whether Yorkville still uses the appendix today is not clear from public records. We found no later Yorkville code update, and the state's online code directory still lists the 2009 codes Yorkville reported in 2014, though the directory is only as current as each town's last report. If you are looking at land there, ask the city which code and appendices it enforces now. Anywhere else, ask your building department which code edition and which appendices it uses.

Minimum house size

We found no statewide minimum house size and no state law that limits local minimums. A 2025 bill, the Tiny Homes Act (HB 2411), would have licensed tiny home parks and set standards for them. It was sent back to committee in March 2025 without a vote.

Tiny homes on wheels

We found no category in Illinois law for a tiny home on wheels, so it falls into the state's other definitions.

  • The Illinois Vehicle Code defines a recreational vehicle as a camping trailer, motor home, travel trailer or other camper "used primarily for recreational purposes."
  • The state campground law lists the park model home as a kind of recreational vehicle, "primarily designed as temporary living quarters." A park model is a small RV built to look and live like a cottage.
  • The state mobile home park law defines a manufactured home as at least 8 feet wide, 40 feet long and 320 square feet, built for year-round living, and it "excludes campers and recreational vehicles."

How these fit a home on wheels lived in full time is not settled. A tiny home on wheels built as an RV or park model is closest to the campground law's definition, which names the park model home. But the Vehicle Code's definition turns on recreational use and the campground law's on temporary living quarters, so neither was written for a full-time home. If the trailer itself is homemade, the state's homemade trailer title rules apply, covered below. Neither label tells you where you can live in it. That is a local zoning question, so get your city or county's answer in writing before you buy land or a home.

A homemade trailer, one built from parts with no manufacturer's papers, is titled through the Illinois Secretary of State. You send an affirmation that it is homemade, a statement of how it was built, four photos and the fees, and the Secretary of State Police inspect it before a title is issued. A trailer of 5,001 pounds or more also needs an Illinois Department of Transportation inspection. A trailer that came with a manufacturer's ownership document does not meet that definition, even if you build the house on it yourself.

Campgrounds and parks

The Illinois Department of Public Health licenses campgrounds, and it licenses manufactured home communities with 5 or more sites, except those in home rule units. Ask each park whether it takes tiny homes or park models for long stays, and in which months.

Modular and manufactured homes

The Illinois Department of Public Health reviews the plans for every modular home model placed in Illinois and keeps a list of approved manufacturers. Manufactured homes are built to the federal HUD code. Since December 31, 2001, every manufactured home must be installed by an Illinois licensed installer or by the homeowner, following the maker's instructions, or the state installation code if those are not available. Any manufactured home moved since January 1, 1980 must be tied down with equipment that meets state standards, and the homeowner is responsible for it.

We found no Illinois law that stops a city or county from keeping manufactured homes out of a zone. A 2025 bill (HB 2999) would have barred zoning rules that keep out a manufactured home that is compatible with the area and meets the same design standards as other homes there. It was sent back to committee in March 2025 without a vote.

ADU rules

Illinois has no statewide ADU law. Several bills to require cities to allow ADUs were filed in 2025 and 2026, and none passed.

  • HB 1813 cleared the House Housing Committee 18 to 0 in March 2025, then went back to the Rules Committee in April 2025 without a floor vote.
  • HB 1709 (2025), SB 3726 (2026) and SB 4071 (2026) have not left committee.
  • HB 5626 (2026), a broader housing bill that would require cities and villages to allow ADUs in every zone that allows single-family homes, was sent to the Rules Committee in February 2026 and has had no vote.

The legislature's two-year session runs into January 2027, and its veto session is scheduled for November 17 to 19 and December 1 to 3, 2026, so a housing bill could still move. Until one passes, your city or county decides.

Chicago has its own ADU rules. The city's ADU ordinance, first approved in 2020, created five pilot areas, and in September 2025 the City Council voted to expand it. The expansion took effect April 1, 2026, in 34 of the city's 50 wards, according to WTTW. Chicago allows two kinds of ADU, a conversion unit in an attic or basement and a coach house, a separate building on the lot. You apply for pre-certification with the Department of Housing first, then for a building permit, and the city notes that pre-certification "does not automatically guarantee that your project is permissible." If you add two or more ADUs to a building, half of them must be kept affordable to households earning up to 60 percent of the area median income. Check your address on the city's ADU map.

Check deed restrictions and HOA covenants too, since they can limit what you build.

Septic and composting toilets

The Illinois Department of Public Health sets the septic rules, and about 90 local health agencies review plans across the state. You need plan approval from the state or your local health department before you build any part of a new system. A new private system is generally not approved if a public sewer is within 300 feet of the property, unless a physical barrier or local ordinance prevents the connection. Where creviced limestone is close to the surface, the drain field needs at least 4 feet of soil above it.

An owner who lives in a single-family home may install, maintain and clean their own system without a contractor license, but still has to follow the state rules. Otherwise, a licensed installer must be on site.

The state code lists compost toilets among the approved ways to handle human waste, along with privies, portable, recirculating and incinerating toilets. A compost toilet must meet NSF/ANSI Standard 41 and carry the seal of NSF or another approved certifier, and the owner must maintain it and dispose of its contents under the state rules. Kitchen and shower water still goes to a regular system, which can be sized 25 percent smaller, with a septic tank of at least 750 gallons. Read the good, the bad and the ugly of composting toilets before you decide.

Wells

New wells must meet the minimum distances from septic systems and other sources set in the state's water well code. Ask your local health department about well permits.

Floods and earthquakes

  • Building in the floodway of a river, lake or larger stream needs a permit from the Illinois Department of Natural Resources. Its permits cover streams draining at least one square mile in urban areas and ten square miles in rural areas, and where no floodway is mapped, the department generally requires permits for work anywhere in the floodplain. Nearly every Illinois community also has its own floodplain rules.
  • The New Madrid Seismic Zone, a fault zone about 150 miles long, reaches into southern Illinois. Ask your building department what the code requires there.

Where to start

  1. Not sure which office covers your land? USA.gov's local government finder points to a directory of Illinois's counties and cities, with their websites and contacts.
  2. Call the city or village planning department, or the county zoning office if the land is outside town. Ask whether tiny homes and ADUs are allowed, the minimum house size, and whether a tiny home on wheels can be lived in there. Get the answer in writing.
  3. Ask the building department which residential code and edition it uses, and whether it adopted the tiny house appendix. The Capital Development Board's Illinois Municipal Code Directory lists the codes each city and county has reported to the state, but an entry is only as current as the last report. If the county has no code, ask what it expects from an owner who builds.
  4. If the land is not on sewer, ask the local health department about septic plan approval and soil tests before you buy.
  5. Check the flood map before you buy land, and ask about floodplain permits.
  6. For a manufactured home, hire an Illinois licensed installer. For a modular home, check that the maker is on the state's approved list.
  7. For a homemade tiny home on wheels, plan for the Secretary of State inspection before you can title it.
  8. In Chicago, check your address on the city's ADU map and apply to the Department of Housing first.

Living in Illinois

How Illinois compares with the other 49 states on the things people weigh before a move. Figures as of November 2026.

  • Happiness score (WalletHub 2026). 51.53 out of 100, 26th happiest
  • Cost of living (MERIC, Q2 2026; U.S. average is 100). 94.5, 24th lowest
  • State income tax. Flat 4.95 percent
  • Property tax, effective rate on owner-occupied homes (Tax Foundation, 2024 data). 1.88 percent, 2nd highest
  • Homeowners insurance, average a year with $400,000 in dwelling coverage (NerdWallet 2026; U.S. average $2,490). $3,240
  • Health care (U.S. News 2026). 27th
  • Education (U.S. News 2026). 13th
  • Average temperature, 1991 to 2020. 52.6 degrees F
  • Average precipitation, 1991 to 2020. 40.7 inches a year
  • Sunshine in Chicago. 54 percent of daylight hours, 84 clear days a year
  • People 65 and older (2024). 17.9 percent

Illinois's cost of living is below the national average, and the flat state income tax is 4.95 percent. The effective property tax rate is 1.88 percent. Homeowners insurance averages $3,240 a year with $400,000 in dwelling coverage, compared with a U.S. average of $2,490. U.S. News ranks Illinois 13th in education and 27th in health care, and WalletHub ranks it 26th happiest.

Rankings mix many factors, and statewide averages hide big differences between regions. Chicago and its suburbs, the central farm country and the hills of southern Illinois differ in weather, land prices and local rules, so look at the area where you plan to live.

Tiny home communities in Illinois

We found few Illinois tiny home communities that publish their details online, and many directory listings for the state could not be traced to a real operator. As of October 28, 2026, we could not confirm on its own website any Illinois community or RV park that takes tiny homes or park models for year-round living. Rules, prices and openings change, so contact any community directly before you plan around it.

Tours we have filmed in Illinois

We do not have an Illinois tour to list here yet. When we do, it will be listed here. Our tours from other states are at Tiny Home Tours by State.

Get new tours and guides

Every other Friday we send real tours, results from our audience polls, and parking and legal lessons from people living tiny. Join the Tiny Home Tours newsletter.

Frequently asked questions

Is it legal to live in a tiny house in Illinois?

Yes, on a permanent foundation, if it meets the building code your city or county uses and local zoning, with sewer or an approved septic system. For a tiny home on wheels, local zoning decides.

Does Illinois have a statewide building code for tiny homes?

Not one code. Since January 1, 2025, every city and county building code must regulate a home's structure at least as strictly as the least strict International Residential Code edition published in the current year or the 9 years before it. The tiny house appendix is not adopted statewide, but a city or county can adopt it, as Yorkville did in 2019.

Can I live in a tiny home on wheels in Illinois?

It depends on your city or county. A tiny home on wheels built as an RV or park model is closest to the state's recreational vehicle definitions, though those definitions describe vehicles for recreation or temporary living, and we found no state law that allows or bans living full time in one. Local zoning decides.

Can I build a backyard tiny house in Illinois?

It depends on your city. Illinois has no statewide ADU law, and the bills filed in 2025 and 2026 did not pass. Chicago allows ADUs in eligible areas since its expansion took effect April 1, 2026. Ask your city or county.

Can I use a composting toilet in Illinois?

Yes, if it is certified to NSF/ANSI Standard 41. The state septic code lists compost toilets as an approved method. Kitchen and shower water still needs a regular system, which can be sized smaller, and you need plan approval from your local health department or the state before you build it.

Sources

This page explains the rules in general terms and is not legal advice. Local rules vary. Confirm with your city or county before you buy land or a home.

Hero photo: Garden of the Gods, Shawnee National Forest, by Haley Hamilton on Unsplash.

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