Barndominium Builders in Multnomah County, Oregon
Multnomah County is mostly city: Portland, Gresham and the smaller east-side towns cover the bulk of its people. The rural part is smaller but real, from the hills west and north of Portland to the farm and nursery country around Corbett and the Columbia River Gorge, and that is where a barndominium with acreage becomes realistic. It is also where the rules are tightest. The county's land use planners describe their job as protecting forest land, farm and nursery production, wildlife, streams and scenic views, and the east end of the county reaches into the Columbia River Gorge National Scenic Area, which has its own review. So on rural land here, zoning comes first and the building design second. We supply barndominium kits for owners who will erect their own shell, produce custom plans that fit the zone's size and siting rules, and carry projects through as turnkey builds, including site preparation. A pole barn home frame is a natural fit for rural ground where the zone allows a dwelling. For a lot inside a city, see our Portland and Gresham pages. Otherwise, send the parcel through the survey and we will start with the zoning and septic questions.
Multnomah County at a glance
- County
- Multnomah County
- Building permit
- County building program
- Land use
- County farm, forest and rural zoning
- Wastewater
- Septic via the county, for DEQ
Barndominium Kits and Plans for Multnomah County
The parcel decides the budget more than the floor area does, so each option is priced against your land rather than a rate card.
Barndominium Kits
Barndominium kits and shell kits for Oregon land, sized to the snow, wind and seismic values the state's design hub gives for your exact site.
Custom Plans
Custom barndominium plans drawn for Oregon's residential code, your site's snow and seismic values, and the energy chapter a steel shell must meet.
Pole Barn Homes near Multnomah County
A pole barn home sets its frame on posts and trusses (the engineering term is post-frame), which often suits a simple, wide layout with a shop bay under the same roof. Whether it fits your parcel comes down to the zoning and the site, set out below.
Permits, Zoning and Septic in Multnomah County
In Oregon the land-use answer often comes before the building answer. Here is who decides each part in Multnomah County, taken from the office or document that publishes it. Rules change, so check them again against your parcel before anything is drawn.
Multnomah County building department (listed by the state directory at Gresham City Hall), with zoning plan review by Multnomah County Land Use Planning
The county issues permits for its unincorporated areas only; Portland, Gresham, Fairview, Troutdale and Wood Village each permit inside their own limits. When you apply for a building permit on most unincorporated land, the permitting city refers you to county Land Use Planning, which reviews the plans for zoning compliance, and any land use permit must be approved before that review.
Source: Submitting a Building Plan for Zoning Review, Multnomah County (multco.us)
Multnomah County Land Use Planning (Department of Community Services)
County Land Use Planning zones the rural, unincorporated county and says its role is to protect forest lands, farm and nursery production, wildlife, streams, scenic views and the Columbia River Gorge. Rural parcels carry farm, forest or rural residential zoning, and whether a new dwelling is allowed depends on that zone and, in the Gorge, on the National Scenic Area rules.
Source: Land Use Planning, Multnomah County (multco.us)
Portland Permitting & Development septic program, acting for DEQ and Multnomah County
Under an intergovernmental agreement with Multnomah County and DEQ, the City of Portland administers the state's onsite septic rules for all of Multnomah County, acting for DEQ. On unincorporated land a Septic Review Certification is part of the process, and septic approval is needed before the final building permit.
Source: Septic Evaluations: Septic Review Certifications, Authorization Notices and Site Evaluation Reports, Portland.gov (portland.gov)
- Columbia River Gorge National Scenic Area
- Multnomah County was the first county with land in the Columbia River Gorge National Scenic Area to adopt regulations implementing its Management Plan; they took effect on 22 June 1993, and the county says it has since reviewed over 200 development proposals against the scenic, cultural, natural and recreational guidelines (page last reviewed 23 March 2026).
- Urban pockets run by cities
- The county's zoning page points to a map of County Urban Pocket Areas, described as unincorporated areas administered by local cities under agreements with the county, and to a Metro lookup that shows whether an address is inside the urban growth boundary or in an urban or rural reserve.
- Rural reserves
- Metro describes rural reserves as high-value working farms and forests or lands with important natural features, protected from urbanization for 50 years after designation, until at least 2065. Metro adds that the designations do not change current zoning or restrict uses already allowed.
Source: Columbia River Gorge National Scenic Area, Multnomah County (multco.us)
Source: Zoning Code and Maps, Multnomah County (multco.us)
Source: Urban and rural reserves, Metro (oregonmetro.gov)
Building on land near Multnomah County
Rural parcels in Multnomah County sit in a few distinct settings, each with its own constraints: forested hills on the west side, farm and nursery ground on the east side, river lowland, and scenic-area land along the Gorge. Before buying, get the zone from the county's planning map and ask the planner on duty whether a dwelling is allowed outright, needs review, or is not possible at all. Check early whether the ground can take a septic system, since there is no sewer out here and a failed site evaluation can end a plan. Slope, tree cover and nearness to a river or stream all shape where a building can sit and how much ground work it needs.
Other places in this part of Oregon
Portland Metro & the Northern Willamette Valley
- Portland
- Gresham
- Hillsboro
- Beaverton
- Oregon City
- Multnomah County
- Washington County
- Clackamas County
Have land in or near Multnomah County? Tell us about the parcel and what you want on it, and we will check it against the local rules before anything is drawn.
Building in Multnomah County: questions
Start the surveyWhat does it cost to build a barndominium in rural Multnomah County?
Do I need a building permit for a barndominium in Multnomah County?
Can I build a barndominium on farm or forest land in Multnomah County?
Who handles septic for a rural home in Multnomah County?
Keep reading
What usually comes next once you know what Multnomah County allows.
Barndominium Cost Guide
Sourced per-square-foot ranges by tier and size, and what moves the number on your land.
Read itIs a Barndominium Legal in Oregon?
Zoning, farm and forest land, septic and who inspects, before you buy the land.
Read itHow Long Does It Take?
From parcel to move-in, and which steps set the clock.
Read itSources for this page
The published pages behind the Multnomah County facts above. Rules change, so check the current version with the office before you rely on it.
- Submitting a Building Plan for Zoning Review, Multnomah CountyBuilding permit authoritymultco.us
- Land Use Planning, Multnomah CountyLand use and zoningmultco.us
- Septic Evaluations: Septic Review Certifications, Authorization Notices and Site Evaluation Reports, Portland.govSewer or septicportland.gov
- Columbia River Gorge National Scenic Area, Multnomah CountyColumbia River Gorge National Scenic Areamultco.us
- Zoning Code and Maps, Multnomah CountyUrban pockets run by citiesmultco.us
- Urban and rural reserves, MetroRural reservesoregonmetro.gov
Other places near Multnomah County
Nearby places with their own pages. Across a city limit or a county line the permit office, the zoning and the septic rules can change, so each is covered separately.
Building in Multnomah County?
Start with the survey. Tell us where the land is and what you want on it, and we will come back with which offices decide it, what the zoning allows, and a plan to fit.