Barndominium Builders in Washington County, Oregon
Washington County has two very different halves. The eastern half is the suburban belt of Beaverton, Hillsboro, Tigard, Aloha and their neighbours, largely inside the regional urban growth boundary; the western and northern half is Tualatin Valley farmland, nurseries and forested foothills. A barndominium with acreage, a shop and room for animals belongs in that second half, and that is the ground this page covers. It is also where zoning does the most work: large parts of the valley floor are zoned for farm use, wooded hills tend toward forest zoning, and rural residential land is the smaller share. A buyer's first question should be whether the zone allows a dwelling, not how big the shop can be. On rural parcels we supply barndominium kits for owners who will raise their own shell, prepare custom plans to the county's siting rules, and take projects through as turnkey builds with site preparation. A clear-span pole barn home is a common choice for farm-style properties where a house is allowed. For lots inside the cities, see our Hillsboro and Beaverton pages. Send the parcel through the survey and we will check the zone and septic outlook first.
Washington County at a glance
- County
- Washington 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 Washington 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 Washington 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 Washington County
In Oregon the land-use answer often comes before the building answer. Here is who decides each part in Washington County, taken from the office or document that publishes it. Rules change, so check them again against your parcel before anything is drawn.
Washington County building department (Hillsboro), for unincorporated land
The state's Local Building Department Directory lists Washington County's building department in Hillsboro for the unincorporated county, and notes that the county provides building services for most unincorporated areas. Cities such as Hillsboro, Beaverton, Tigard, Forest Grove, Cornelius, Sherwood and Tualatin run their own permit offices inside their limits.
Source: Local Building Department Directory, Building Codes Division (oregon.gov)
Washington County Department of Land Use & Transportation (county planning); Metro for the growth boundary and reserves
Outside the urban growth boundary, county zoning decides whether a house is allowed: exclusive farm use, forest and rural residential zones each treat a new dwelling differently. Some land next to the boundary is also designated by Metro as rural reserve, protected from urbanization until at least 2065, though Metro says the designation does not change current zoning.
Source: Urban and rural reserves, Metro (oregonmetro.gov)
Washington County Environmental Health (Department of Health and Human Services), DEQ's onsite agent for the county
DEQ's list of county onsite septic agents names Washington County Environmental Health, part of the county's Department of Health and Human Services in Hillsboro, as the office acting for DEQ in this county. It handles the site evaluation and the septic permit for rural parcels without sewer.
Source: Onsite Septic Staff and County Agent Contact Information, DEQ (oregon.gov)
- Sewer stops near the boundary
- Clean Water Services provides sewer with 12 partner cities to more than 600,000 people in the urban areas of the Tualatin River watershed, an area it says closely follows the urban growth boundary. Rural parcels beyond that line generally depend on an onsite septic system.
- Recent boundary changes in the county
- Metro's list of recent urban growth boundary expansions includes a 2024 decision for Sherwood, a 2023 Tigard River Terrace 2.0 boundary exchange and a 2018 decision covering Beaverton, Hillsboro and King City among others (Metro page read 26 September 2026).
Source: Who & Where We Serve, Clean Water Services (cleanwaterservices.org)
Source: Urban growth boundary, Metro (oregonmetro.gov)
Building on land near Washington County
Rural Washington County parcels range from flat valley farmland to wooded slopes in the Coast Range foothills. On exclusive farm use land a dwelling has to qualify under state tests and county review, and a non-farm home can end the land's farm tax deferral; forest zones have their own dwelling tests. Rural residential zones are the more direct path to a house, but such parcels are harder to find. Beyond zoning, check that the soil will pass a septic site evaluation, that a well is feasible, and that the parcel has legal road access. Creeks feeding the Tualatin River bring floodplain and wetland questions on low ground. Land next to the growth boundary may be an urban or rural reserve, which tells you its long-term future.
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 Washington 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 Washington County: questions
Start the surveyHow much does a barndominium cost to build in rural Washington County?
Do I need a building permit for a barndominium in Washington County?
Can I put a barndominium on farmland in Washington County?
Where do Aloha and Tigard buyers look for a barndominium?
Keep reading
What usually comes next once you know what Washington 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 Washington County facts above. Rules change, so check the current version with the office before you rely on it.
- Local Building Department Directory, Building Codes DivisionBuilding permit authorityoregon.gov
- Urban and rural reserves, MetroLand use and zoningoregonmetro.gov
- Onsite Septic Staff and County Agent Contact Information, DEQSewer or septicoregon.gov
- Who & Where We Serve, Clean Water ServicesSewer stops near the boundarycleanwaterservices.org
- Urban growth boundary, MetroRecent boundary changes in the countyoregonmetro.gov
Other places near Washington 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 Washington 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.