What are the tiny house laws in Oregon?

Oregon allows permanent small homes, but you need both construction approval and land-use permission¹. Meeting Oregon's construction standards does not mean you can put the home on your chosen parcel¹. Ask your city or county planning office whether your proposed residential use is allowed¹.

The Oregon Building Codes Division adopts, amends and interprets the specialty codes that form the state building code⁴. Its Residential Structures Code Program covers construction, reconstruction and repair of houses and townhouses⁸. Before you order a home, ask BCD which current code applies to your design⁸. Tell the office whether you want permanent housing or temporary accommodation, because local governments control temporary tiny-home use².

Oregon's 400-square-foot threshold defines the small-home category and does not set a minimum floor area for every house¹. We could not confirm a single minimum size for your home, so ask BCD which construction standards apply to your design⁸. Ask about sleeping lofts, access and room dimensions before you choose a floor plan⁸.

Oregon offers qualifying owner-builders a limited exemption for ceiling heights, room sizes and maintaining specified temperatures⁵. As the intended owner-occupant, you must build the entire home, with unpaid help from friends and relatives allowed⁵. You must not have used the exemption during the preceding 5 years⁵. You still need to meet other building-code, building-permit, inspection, land-use and utility requirements⁵. A noncompliant structure also brings permanent deed-record filing requirements for the building permit⁵.

Your local city council or county commission sets the rules for temporary tiny homes on wheels in Oregon². The state's statement of local authority does not give you permission to live in a trailer on any private lot². Tell the planning office whether you intend to live there temporarily, rent the space or establish a permanent home.

You can use Oregon's rural RV rental law only if your county chooses to allow the use⁹. The property needs an owner-occupied primary dwelling and must be outside an urban reserve⁹. The tenant must own or lease the RV, and the property owner must supply essential services⁹. Vacation occupancy and other short-term uses do not qualify⁹. Oregon also protects RV occupancy in specified park and disaster settings, with conditions set by law¹⁰. Those protections do not give you unrestricted permission to live in an RV on vacant land¹⁰.

Klamath County in Oregon allows qualifying small dwellings that meet the residential code it applies³. In Curry County, your tiny home must be built and licensed as a manufactured home on a permanent foundation, with placement and utility rules³. These county answers cover unincorporated land; they do not give you blanket permission inside city limits³.

The tiny-home answers here cover 13 of Oregon's 36 counties: 2 allow qualifying homes, 9 have limited paths and 2 prohibit the stated uses³. The remaining 23 counties have no answer here, so you cannot infer permission or prohibition³. Check which uses each answer covers. A temporary housing exception or campground rule does not give you permission for a permanent home³. Use the Oregon tiny-home county comparison to find the conditions that apply before you compare parcels³.

Oregon requires local governments to allow ADUs within urban growth boundaries in areas zoned for detached single-unit dwellings¹¹. This requirement covers cities above 2,500 people and counties above 15,000 people¹¹. Those local governments must allow at least 1 ADU for each detached single-unit dwelling in the qualifying area¹¹. These location limits leave unanswered whether you can add a tiny home on rural acreage¹¹.

Local ADU rules can cover where you put the home and how you design it¹¹. For qualifying ADUs, local rules cannot require you to live on the property or build extra off-street parking¹¹. Vacation occupancy has separate exceptions to those restrictions¹¹. Ask your planning office whether your address falls within the mandate and whether your proposed structure qualifies as an ADU¹¹.

Oregon septic approval can determine whether an undeveloped parcel works for your home⁶. If your site has never been evaluated, you need a septic site evaluation⁶. You need the applicable septic permit for new construction, alterations and repairs⁶. DEQ needs an affirmative Land Use Compatibility Statement before issuing a septic construction permit for new construction or alterations⁶. Ask whether wastewater disposal is possible before you commit to the parcel.

Oregon DEQ assigns onsite septic work to county agents in some areas¹². Use DEQ's county-agent directory to find the office serving your address¹². Your building still needs a sewer connection within a sewer district, even if you install a composting toilet⁷. Ask the issuing office for current septic fees. Ask the building office for a written estimate covering your specific design. Discuss your parcel with the offices that handle construction, lawful residential use and wastewater disposal^1,2,6.