Can You Put a Tiny House in Your Backyard? Permit Rules

Short answer: a tiny house on wheels is usually treated as an RV, and only some cities, like Portland, Boise, Port Townsend, and San Luis Obispo, allow one in a backyard under specific permits. A tiny house on a foundation is a house and needs a building permit. Either way, the utility connections usually need permits.

Tiny houses look like the perfect backyard answer to a lot of problems: a place for an aging parent, a grown kid who can't afford rent, a home office, or a small rental that helps with the mortgage. You can buy one online, have it towed in on a trailer, and park it behind the garage in an afternoon. That ease is exactly where the trouble starts. Whether you can legally put a tiny house in your backyard, and especially whether anyone can live in it, depends far less on the house than on two questions your city will ask: what standard was it built to, and does your zoning allow it?

This guide walks through those questions using official rules from cities, counties and state agencies in Oregon, Washington, Idaho, California, Minnesota, Arizona, North Carolina and New Hampshire. Some of them welcome tiny houses on wheels in backyards. Others flatly do not allow anyone to live in one outside an RV park. Where the rules conflict, we show both sides rather than pretending there is a national answer.

The short answer

• A tiny house on wheels is usually treated as an RV. California's housing department says RVs "are not intended for occupancy as a permanent dwelling" and, unless a local ordinance allows otherwise, generally may be occupied only in mobilehome or special occupancy parks (California HCD).
• Some cities now allow them in backyards anyway, under specific permits. Portland, Boise, Port Townsend and San Luis Obispo all have written rules for a tiny house on wheels behind an existing home.
• Others don't. Duluth, Minnesota does not treat trailers or self-propelled vehicles as permanent dwellings and allows them only in seasonal camps and RV parks (City of Duluth).
• A tiny house on a permanent foundation is a house. It goes through a normal building permit, and many departments point to the tiny house appendix of the International Residential Code for relaxed rules on lofts and ceiling heights.
• Utilities almost always need permits, even where the tiny house itself only needs a zoning or site permit.

Step one: figure out what kind of "tiny house" you have

There is no single legal category called "tiny house." Permit Sonoma says so plainly: "There is no industry standard definition of a tiny house," and the permitting and inspection requirements differ for each type (Permit Sonoma). California's Department of Housing and Community Development (HCD) lists the categories a tiny home has to fit into before it can be occupied legally: a site-built home meeting the state building code, factory-built housing, a HUD-Code manufactured home, a recreational vehicle, a park trailer, or a camping cabin. A structure that fits none of them is, in HCD's words, "a noncomplying residential structure in which occupancy is illegal."

In practice, most tiny houses land in one of four groups:

• Site-built on a foundation. Built in your yard like any small house, reviewed under the residential building code.
• Factory-built (modular) on a foundation. Built off site to the building code, inspected in the factory, then set on a foundation with a local permit. In Washington, the state Department of Labor and Industries (L&I) approves these as factory-built housing, and only if they meet the state building code (Washington L&I).
• Manufactured home. Built to the federal HUD code on a permanent chassis. HCD's definition is a home that is 320 square feet or more when set up, so the smallest tiny models fall outside it.
• Tiny house on wheels (THOW), park model RV or RV. Built on a trailer chassis, usually to an RV standard. HCD notes that RVs built since July 14, 2005 follow the NFPA 1192 standard, and park trailers follow ANSI A119.5 and NFPA 1192, with a 400-square-foot limit when set up.

Before you buy, ask the seller in writing which of these your unit is and what certification label it carries. Washington L&I points out that it "can only approve the construction" of RVs, park models and modular buildings, "not how they are used or where they can be located." That part belongs to your city or county.

Tiny houses on wheels: can you live in one in your backyard?

Where the answer is no

Many places still treat a tiny house on wheels exactly like a camper. Duluth's 2026 FAQ says tiny houses on wheels that are self-propelled or permanently towable are recreational vehicles, that they "do not meet minimum health and safety standards" of the Minnesota Residential Code for a permanent dwelling, and that they are not allowed in any zone except seasonal camps and RV parks. Burke County, North Carolina says you can't live in a recreational vehicle as a permanent residence, and while you may store an RV on private land, zoning does not allow power or other utilities to be connected to it outside an approved campground or RV park (Burke County, NC). Barrington, New Hampshire says units built to the ANSI A119.5 park model standard "are not suitable as dwellings" in the town for more than 180 days (Town of Barrington).

Where the answer is yes, with a permit

A growing number of cities have written rules that let homeowners host a tiny house on wheels behind an existing home:

• Portland, Oregon allows one occupied RV or tiny house on wheels on a residential lot with a house, attached house or manufactured home. The wheels must stay on, it can't sit in front of the street-facing side of the house, it must be at least five feet from the primary dwelling, and it is not allowed on undeveloped lots (Portland.gov).
• Boise, Idaho has allowed tiny homes on wheels in some zoning districts since July 1, 2025. Up to two are allowed per parcel as an accessory use to a single-family home, each no larger than 400 square feet, certified to the NOAH+ standard or another city-approved standard (City of Boise).
• Port Townsend, Washington has permitted tiny houses on wheels as accessory dwelling units since July 1, 2023, with up to two on a lot that already has a single-family home (Port Townsend FAQ, January 2026).
• San Luis Obispo, California allows one tiny home on wheels in the backyard of an owner-occupied single-family home through a Director's Action Permit (City of San Luis Obispo).

Where official rules disagree

Even the cities that say yes don't agree on the details. These differences decide which tiny house you can buy, so check them before you pay a deposit.

Two conflicts stand out. First, wheels on or off: Portland says the wheels must remain on to stay mobile, and San Luis Obispo says a tiny home on wheels "shall not have its wheels removed," while Port Townsend says the unit "cannot be supported solely by wheels" and typically has them removed and stored underneath, resting on pads and piers. Second, park models: Port Townsend accepts a park model RV that meets its extra design standards, while Boise's definition requires NOAH+ or another approved standard and lists park model RVs among the recreational vehicles that are "not year-round dwellings." A unit that is legal in one city can be the wrong product in the next.

Tiny houses on a foundation: the building permit route

If the tiny house sits on a permanent foundation, it is a dwelling, and it is reviewed like one. Boise's building division says tiny houses "need to be on a permanent foundation" and are built under the one- and two-family dwelling code, with the exceptions in the code's tiny house appendix (Boise Building Division). Barrington requires a foundation meeting Chapter 4 of the 2018 International Residential Code, construction drawings, a site plan, an approved septic design and water source, inspections throughout, and a certificate of occupancy before anyone moves in. Burke County says a tiny home plan that meets the North Carolina residential code may be approved, starting with a zoning permit and then a building permit.

What the tiny house appendix changes

The 2018 International Residential Code includes Appendix Q for tiny houses (its sections are numbered AQ101 and up). It defines a tiny house as a dwelling of 400 square feet or less, not counting lofts, and relaxes a few rules that make small homes hard to design. Boise summarizes the main ones:

• Ceilings in living space and hallways at least 6 feet 8 inches; bathrooms and kitchens at least 6 feet 4 inches. Lofts can be lower.
• Lofts at least 35 square feet and at least 5 feet in every horizontal direction, with guards at least 36 inches tall or half the clear height to the ceiling, whichever is less.
• Lofts can be reached by compact stairs, ladders, alternating tread devices or ship's ladders.
• A sleeping loft can use an egress roof access window if the bottom of the opening is no more than 44 inches above the loft floor and it meets the normal escape-opening size.

Not every jurisdiction uses this appendix. Pima County, Arizona builds and inspects tiny houses under the 2018 IRC Appendix Q (Pima County, AZ), but Duluth simply says a fixed tiny house must be big enough to meet the Minnesota Residential Code. Ask your building department which code edition and appendices it has adopted. Escape openings still matter either way; our egress window guide explains the basic sizes, and new dwellings also need alarms like those in our smoke and CO alarm guide.

Zoning still decides whether a second home fits

A code-compliant tiny house in the backyard of an existing home is usually an accessory dwelling unit (ADU), so your local ADU rules apply. Duluth, for example, caps an ADU at 800 square feet and asks for an extra off-street parking space. Pima County allows tiny houses on permanent foundations in any zone that allows detached single-family homes, but treats tiny houses on a mobile chassis as trailers allowed only in a short list of zones. Our backyard ADU permit guide covers size caps, owner-occupancy and parking, and the garage conversion and ADU guide covers the zoning side. If you were thinking of a converted container instead, see shipping container permits.

Factory-built tiny houses add one more layer. Boise says modular tiny houses must be permitted by the state and by the city before being placed on a foundation, and Washington L&I won't approve a dwelling built on the site where it will be used, a conversion of a shed or container done on site, or a HUD manufactured home as a tiny house; those are left to local building departments.

Utilities: the part that usually needs permits

Even where a tiny house on wheels is not a "building," the water, sewer and power that serve it are. This is where many backyard setups fail an inspection.

• Portland requires an electrical connection through a dedicated outlet on a service pedestal or on the house, on a 20-amp GFCI-protected circuit, with an electrical permit if that circuit doesn't exist yet. One properly rated outdoor extension cord is allowed, but not several joined together. A sewer connection through the house's cleanout needs a plumbing permit, and water can come from an anti-siphon hose bibb using a potable-water hose.
• Port Townsend goes the other way: "no extension cords are allowed" from the house, no garden hoses or composting toilets, a separate electrical permit from L&I, a city plumbing permit for the water and sewer extension, and county health department approval if the lot is on septic.
• Boise requires connection to central water and sewer, usually through the main home's connection, bans generators as a power source, and says a licensed contractor must apply for the water, sewer and electrical permits.
• San Luis Obispo requires a building permit to set up safe water, sewer and electrical connections.
• Sonoma County requires temporary units to connect to the parcel's septic or sewer system, or to keep a pump-and-haul contract with a licensed contractor for the whole permit term.

Our guides to electrical permits for new circuits, private sewer line work, septic permits and clearances and private well permits explain how those separate permits usually work.

Utility hookups for a backyard tiny house on wheels

Sources: City of Portland, City of Port Townsend, City of Boise, City of San Luis Obispo, Permit Sonoma.

The pad, setbacks and placement

Where tiny houses on wheels are allowed, the cities say a lot about where and how they sit:

• Location: Boise wants the unit behind the main home; San Luis Obispo wants it toward the rear without blocking required parking; Portland keeps it out of the area in front of the house.
• Separation: Portland requires 5 feet from the primary dwelling, Port Townsend 5 feet from any other structure, and Boise 6 feet from other structures. Duluth notes that any building closer than five feet to a property line may need a fire wall.
• Pad: Boise requires a stable pad such as concrete, asphalt or pavers, anchored against movement. Port Townsend accepts concrete, asphalt, compacted gravel or decomposed granite, with at least four hold-down devices. San Luis Obispo accepts concrete, paving or compacted gravel. A new slab or gravel pad can raise its own drainage and lot-coverage questions; see our patio and pad permit guide.
• Looks: Boise and Port Townsend want skirting around the chassis and siding and roofing that look residential. Port Townsend says the unit "must not look like an ordinary RV or trailer."
• Setbacks and coverage: every city above applies normal zoning setbacks, and Port Townsend counts the unit toward lot coverage.

If you're tight on space, read our guides on checking setbacks and easements before you buy and zoning variances. An HOA can ban a tiny house even where the city allows it, so check HOA approval vs. the city permit too.

Living in it temporarily: while you build, or for a relative

Here the official answers really do split. Sonoma County issues a Temporary Occupancy permit for RVs and tiny homes on wheels while a house is being built or heavily remodeled (the unit must be removed within 60 days of final approval), before building an ADU, to house an ill or disabled relative or caregiver with a doctor's note, for wildfire survivors, and for some farmworker housing. These are generally allowed for up to one year, and the county says the permits averaged around $400 as of fiscal year 2023-2024. Port Townsend, by contrast, answers "No" to living in a tiny house on wheels while you build your house: the primary home needs its final inspection and certificate of occupancy before a tiny house on wheels can be permitted. Neither Sonoma County nor Portland allows one on land without an established home.

Renting it out

A backyard tiny house can be a long-term rental in some places, but short-term rentals are a common no. Portland, Boise and Port Townsend all prohibit using a tiny house on wheels as a short-term rental (Port Townsend defines that as 29 days or less). Sonoma County bans transient lodging in temporary units but allows long-term rentals subject to housing law. Portland adds that its rental property maintenance rules can apply when the occupant isn't the owner.

What happens if you skip the permits

Port Townsend will "require removal" of a tiny house on wheels installed without a permit unless it can be legalized through after-the-fact permitting, and it won't let you bring a unit onto a permitted pad until the site permit is issued. California's HCD bulletin says enforcement agencies can prohibit occupancy of a tiny home that doesn't meet any recognized standard. Portland's enforcement is complaint-driven, which in practice means a neighbor's call often starts it; our guide to what happens after a neighbor complaint explains the usual process, and after-the-fact permits covers legalizing work. An unpermitted dwelling in the yard can also come up when you sell, as we cover in selling a house with unpermitted work.

A step-by-step plan before you buy a tiny house

1. Decide how it will be used. Full-time home, guest space, office, rental, or temporary housing? Each one can be a different permit.
2. Look up your zoning and search your city or county site for "tiny house," "tiny home on wheels" and "occupied RV." If nothing comes up, call the planning office.
3. Ask which construction standards are accepted: residential code, state factory-built approval, NOAH+, ANSI park model, or none for wheeled units.
4. Confirm wheels-on or wheels-off rules, the pad type, separation distances and setbacks.
5. Price the utilities. Water, sewer or septic and electrical work usually need their own permits and sometimes a licensed contractor.
6. Get approvals before delivery. Boise suggests buying the unit after the planning application is approved, and Port Townsend won't let a unit onto the property until its site and plumbing permits are issued.
7. Keep the paperwork: certification labels, permits and final inspections. You'll want them when you insure, rent or sell.

Our printable 10-minute permit checklist helps with steps 2 to 4, and if you plan to build a foundation tiny house yourself, read about owner-builder permits first. A small non-living backyard structure is a different question; see our shed permit guide.

Questions to ask your planning and building departments

• Can a tiny house on wheels be occupied on a residential lot here, and in which zones?
• Does it count as an ADU, an occupied RV, or something else?
• Which certifications do you accept: ANSI park model, NOAH+, state factory-built approval, or residential code only?
• Must the wheels stay on, or must the unit sit on piers or a foundation?
• What pad, separation and setback rules apply?
• Which permits do the water, sewer or septic, and electrical connections need, and must a licensed contractor pull them?
• Is there a time limit, renewal, or owner-occupancy requirement?
• Can it be rented, and are short-term rentals banned?
• Have you adopted the tiny house appendix of the residential code for foundation builds?

Frequently asked questions

Can I live in a tiny house on wheels in my backyard?

Only where local rules allow it. Portland, Boise, Port Townsend and San Luis Obispo have written permits for it, while Duluth and Burke County, North Carolina don't allow permanent living in an RV outside approved parks. California's HCD says RVs generally may be occupied only in parks unless a local ordinance says otherwise.

Do I need a building permit for a tiny house on wheels?

Usually not for the unit itself, which is certified as a vehicle or park model, but you typically need a zoning, land use or site permit and separate permits for the utility connections. Port Townsend requires a THOW land use permit and a pad and plumbing permit; San Luis Obispo requires a Director's Action Permit plus a building permit for utilities.

How big can a backyard tiny house be?

Most tiny house rules use 400 square feet as the limit: Boise, Port Townsend and San Luis Obispo for wheeled units, and the IRC tiny house appendix for foundation houses, not counting lofts. Port Townsend also sets a 150-square-foot minimum first floor and a 16-foot height limit. A larger unit is usually reviewed as a regular ADU.

Can I put my tiny house on wheels on a foundation later?

Then it is generally treated as a dwelling or ADU that must meet the building code. San Luis Obispo says a tiny home with its wheels removed and placed on a foundation is a dwelling unit or ADU subject to the California Building Code, and Port Townsend says a park model built to ANSI 119.5 "can never be placed on a permanent foundation."

Can I live in a tiny house while I build my main house?

It depends on the county. Sonoma County allows a temporary unit during construction with a Temporary Occupancy permit, removed within 60 days of final approval of the house. Port Townsend says no: the main home has to be finished before a tiny house on wheels can be permitted.

Can I build my own tiny house on wheels?

Sometimes, but it still needs certification. Port Townsend says a THOW must be built off site and permitted and inspected by Washington L&I before it arrives. Pima County accepts off-site builds permitted by a recognized agency or an accredited fabricator.

Can I power a backyard tiny house with an extension cord?

It depends on the city. Portland allows one properly rated outdoor extension cord from a dedicated outlet, while Port Townsend allows no extension cords from the house (Portland, Port Townsend).

Last checked: October 31, 2026.

Official sources

• California Department of Housing and Community Development: Information Bulletin 2016-01, Tiny Homes (PDF)
• Permit Sonoma: Tiny Houses
• City of San Luis Obispo, California: Tiny Home on Wheels
• City of Portland, Oregon: Occupied Recreational Vehicles and Tiny Houses on Wheels
• City of Boise, Idaho: Tiny Homes on Wheels
• City of Boise, Idaho Building Division: Tiny Houses
• City of Port Townsend, Washington: Tiny Houses on Wheels as ADUs FAQ, January 2026 (PDF)
• Washington Department of Labor & Industries: Tiny Homes vs. a Tiny House (PDF)
• City of Duluth, Minnesota: Tiny Houses and Accessory Dwelling Units FAQ, 2026 (PDF)
• Pima County, Arizona: Permitting Regulation for Tiny Houses
• Burke County, North Carolina: Planning and Zoning FAQ
• Town of Barrington, New Hampshire: Construction Guidelines for Tiny Homes (PDF)

Edited by Ahmed Khalifa, founder of PermitCove. Sources are linked inline; see our Editorial Policy.