Washington County, Oregon Building Permit Guide

Washington County is the second-most-populous county in Oregon at about 612,000 residents, the heart of the Silicon Forest technology corridor west of Portland. Unusually for Oregon, it has very large urban unincorporated communities — Aloha, Cedar Mill, Bethany — so its Building Services division, part of Land Use and Transportation, carries a heavy permitting load alongside the cities.

This guide covers Building Services and how to reach it, the uniform statewide code, the county’s large unincorporated role, and where city-limit work goes instead.

This guide covers unincorporated Washington County. Hillsboro, Beaverton, Tigard, Tualatin and most other cities run their own permitting; Cornelius contracts its building services to Forest Grove, and the county issues Cornelius’s electrical permits.

What requires a building permit in Washington County?

Which code applies — OSSC or ORSC

The Oregon Residential Specialty Code (ORSC) governs one- and two-family dwellings and townhouses and their accessory structures; the Oregon Structural Specialty Code (OSSC) governs commercial buildings, apartments of three or more units and everything outside the residential scope. Alongside them sit the mechanical, plumbing, electrical and energy specialty codes, and the Oregon Fire Code is adopted by the State Fire Marshal. In Washington County, Building Services administers the state code for the large unincorporated areas, with land use handled alongside; most cities administer their own.

Oregon’s building code and its exemptions are the same in Washington County as everywhere in the state, and an exemption from the building permit is not an exemption from zoning, land use or a trade permit. Site snow, wind and seismic values come from the state’s Oregon Design Criteria Hub. How Oregon’s statewide code works

Who handles permitting in Washington County?

Building Services, under Land Use and Transportation, handles building permits and inspections for unincorporated Washington County; Hillsboro, Beaverton and most other cities handle their own, and the county also issues electrical permits in Cornelius.

Building Services enforces the state building code for the unincorporated county, and because the unincorporated urban communities here are large, that is a substantial role. Plan-review submittals go through electronic plan review, inspections can be scheduled online or by phone, and most services are available remotely; the in-person counter runs Monday through Thursday.

The Silicon Forest technology base drives large industrial and clean-room projects, while the urban unincorporated communities drive heavy residential volume. Confirm the jurisdiction from the parcel first.

In 2025, building permits issued in unincorporated Washington County authorized 432 new privately owned housing units, 373 of them single-family homes, according to the U.S. Census Bureau Building Permits Survey.

Permit types

Residential permits

Unincorporated residential work is heavy in the urban communities of Aloha, Cedar Mill and Bethany. Re-roofs beyond the exempt scope, solar and EV chargers need permits, seismic detailing applies broadly, and every contractor needs a current CCB licence, apart from casual work under $1,000 and owners working on their own property.

Commercial permits

Commercial and industrial work runs from technology and clean-room facilities to retail and office, all subject to plan review, land use, and the CCB licence requirement, with electrical and plumbing work generally done by state-licensed trades.

Contractors need a current Construction Contractors Board licence with the right endorsement for a job of any size; the exceptions are casual work under $1,000 by someone who does not advertise as a contractor, and owners working on their own property who are not building to sell. Contractor licensing in Oregon

Washington County permit costs and fees

Budget the county building permit and plan-review fees, the statewide surcharge, separate trade permits, and any land-use review. Fees follow Oregon’s statewide valuation method with the county schedule.

Oregon fixes the method rather than the price: new construction is valued with the ICC building valuation data under OAR 918-050-0100, Washington County applies its own schedule, and a 12 percent state surcharge is added to every permit fee. How Oregon permit fees are set

Trade permits and who may pull them

Electricians and plumbers are licensed by the state, though an owner may do electrical work on their own home and plumbing work that is not for hire. An electrical permit is needed for new or altered wiring; like-for-like repairs of outlets, switches and fixtures, and bulb, fuse and small-appliance swaps, are exempt. Electrical and plumbing permits in Oregon

How to apply for a Washington County building permit

An Oregon building permit expires if work does not start within 180 days of issue or stops for 180 days; the building official can extend it in writing, 180 days at a time. Oregon’s statewide code rules

Inspections in Washington County

Standard checkpoints include footing and foundation, under-floor and slab, framing, rough-in electrical, plumbing and mechanical, insulation and energy, fire systems on commercial work, and final, with occupancy approval before use. Technology and clean-room projects add specialised mechanical and electrical verification.

Many Oregon jurisdictions take inspection requests online, several through the state ePermitting system; confirm the method Building Services uses and give the notice it asks for.

Do not cover work before the required inspection has been approved. Keep the issued permit, the approved plans, the seismic and energy documentation, product listings and your correction responses available on site.

Washington County permit search and official resources

Permit records in Oregon sit with the authority that issued them — where Building Services administers the code, it holds the building permit, the inspection history and the certificate of occupancy for work in unincorporated Washington County. Many jurisdictions expose permit search through the state ePermitting portal. If you are buying, refinancing or renovating, confirm that past work was permitted rather than assuming it was.

These are the primary sources behind this guide. Codes, fee schedules and portal procedures change — confirm the position for your filing date.

• Washington County Building Services
• Oregon Building Codes Division
• Oregon Construction Contractors Board (CCB)
• Oregon ePermitting
• Oregon Design Criteria Hub (seismic and site)

Frequently asked questions

Where do I get a Washington County building permit?

From Building Services, part of Land Use and Transportation, in Hillsboro; submittals go through electronic plan review and the in-person counter is open Monday to Thursday, 8 to 4.

Does the county handle a lot of permits itself?

Yes. Washington County has very large unincorporated urban communities — Aloha, Cedar Mill, Bethany — so Building Services is a major permitting authority.

Is the building code different from the cities?

No. Oregon runs one uniform code statewide; what differs is the administering office, the fee schedule and the land-use rules.

Do I need a contractor licence for a small county job?

Almost always. Oregon requires a current CCB licence for construction work of any size; the exceptions are work under $1,000 that is casual, minor or inconsequential, by someone who does not advertise as a contractor, and owners working on their own property who are not building to sell.

Can I file remotely?

Yes. Washington County offers online applications, electronic plan review and phone-based inspection scheduling, with most services available remotely.

How do I run a Washington County permit search?

Use the county’s online permitting portal; the permit and inspection history sit with the authority that issued the permit.

Simplify Washington County permitting with Alliance Permitting

Washington County pairs a major unincorporated permitting role with a heavy technology-industrial base, all remote-friendly through electronic plan review. Confirming jurisdiction and running the electronic submittal cleanly keeps a Silicon Forest project moving.

Trusted by leading builders, developers, and national contractors — 21+ years of filing in the jurisdictions we write about.

Contractors and builders choose Alliance for Washington County because the work is done by people who have stood at the counter:

• We confirm unincorporated-versus-city jurisdiction from the parcel.
• We prepare and submit through electronic plan review.
• We pull seismic and site values from the Design Criteria Hub.
• We verify every contractor holds a current CCB licence.
• We confirm state electrical and plumbing licences for the trades.

Alliance Permitting is a permit documentation and submission company in Oregon. We prepare your paperwork, file it correctly and coordinate with the permitting authority through issuance. We are not a contractor and we do not perform licensed plan review or inspections; that work stays with your licensed team and the jurisdiction.

This guide is provided by Alliance Permitting for general information about Washington County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.