What are the tiny house laws in Idaho?

You can live in a tiny house in some Idaho counties, subject to local conditions¹. These county answers cover unincorporated land; they do not grant permission inside city limits¹. Ask the planning office for your parcel whether you can use your proposed home as a permanent residence.

Idaho adopts specified parts of the 2018 International Residential Code, with Idaho amendments². Local governments that issue building permits and enforce building codes must adopt the codes specified by the Idaho Building Code Act⁵. Before you order a kit or hire a builder, ask the building office which tiny-house rules apply to your plans.

We could not confirm a statewide minimum total house size in Idaho. Ask your local building office what minimum floor area applies to your design. Ask the planning office separately about zoning rules for your parcel.

Latah County sets a minimum dwelling area¹. That minimum applies in Latah County, not across Idaho¹. In Kootenai County, a tiny house on a permanent foundation falls under the county's building ordinance if proposed as a primary dwelling¹. Ask each office to identify the rule that applies to your home. Bring a floor plan showing your bathroom, sleeping space and proposed overall dimensions. Ask for a written response before you pay a builder.

In Idaho, Bonner County treats tiny houses as recreational vehicles and applies RV dwelling-unit rules¹. Jefferson County also applies its RV rules to tiny houses used as primary living quarters outside legal RV or manufactured-home parks¹. Ask the planning office how it will classify your wheeled home before you plan to live in a trailer permanently.

We could not confirm a statewide Idaho rule allowing you to live in an RV on private land. Ask specifically about permanent residence, rather than parking or recreational camping. Describe how long you plan to stay and whether your home will remain mobile. Start with the Idaho RV-living guide to check the separate rules for RVs⁶.

You need an Idaho septic installation permit if you install a subsurface sewage disposal system, unless a stated exception applies⁴. Idaho's public health districts issue these permits⁴. Ask the district for your county about site suitability, applications, fees and existing septic records⁷. Ask for a site evaluation before you buy land for your tiny house⁷.

Idaho DEQ's wastewater guidance sizes an accessory dwelling unit as a single-family dwelling⁸. You can share wastewater flows, but a shared septic tank must have the required capacity for both structures⁸. Ask the health district to assess your existing system before you plan a backyard tiny home. Idaho can deny a septic permit where public or central wastewater facilities are reasonably accessible⁹. Ask about sewer availability before you choose an onsite design.

Before you move into an Idaho manufactured home, DOPL or the authority with jurisdiction must inspect and approve its installation³. Your new manufactured home also needs a DOPL installation permit and tag where there is no approved local building program³. You need that approval before installation starts³. Ask DOPL which construction category fits the home you plan to buy.

For Idaho building and factory-built-structure questions, call DOPL at (208) 334-3233 or email BCRE-PERMITS@DOPL.IDAHO.GOV¹⁰. Send the manufacturer's documentation, your proposed site and how you plan to use the home as a residence. Then ask your local planning office about placement approval. Ask what building permit and septic permit fees apply before you set your budget. Keep the office responses with your purchase documents.