Portland, OR
Portland ADU Permit: do you likely need a permit?
Portland requires building and trade permits to convert a home or garage into an ADU or build a new ADU.
What the official sources say
Portland says to apply for an ADU permit before converting a home or garage or building an ADU. The city states that ADUs can be created by converting part of the house, converting an existing garage or accessory structure, or constructing a new building. Portland requires a building permit for garage or habitable-space conversion and says ADU projects also need electrical, plumbing, and mechanical trade permits.
Likely permit path
- Building permit for ADU construction or conversion of attic, basement, garage, or accessory structure to habitable space.
- Electrical, plumbing, and mechanical permits, which may be submitted with the building permit or later.
- Zoning review for location, height, coverage, setbacks, visitability, adjustment review, or property-specific limits.
Watch-outs
- Portland warns existing spaces may fail living-space requirements because of ceiling height, egress windows, insulation/ventilation, or stairs.
- Permit history matters; prior unpermitted work may need to be permitted as if new.
- Adding an ADU may affect property taxes, which the county assessor determines.
Documents to gather
- Building permit application, site plan, architectural plans, and structural plans if structural changes are proposed.
- Zoning base-zone information, existing permit history, and photos of the conversion area.
- Trade scope, contractor CCB number where applicable, and pre-approved plan selection if used.
Questions to ask before applying
- Is this an ADU, JADU, attached ADU, detached ADU, garage conversion, or non-rental habitable-space conversion?
- What zoning district, overlays, coastal/historic/flood/fire conditions, HOA limits, or deed restrictions apply to the property?
- Will the unit include independent living, sleeping, cooking, and sanitation facilities?
- What building, zoning, trade, utility, addressing, parking, inspection, and certificate-of-occupancy steps apply before occupancy or rental use?
Official sources
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PermitCheckup provides informational permit-readiness guidance based on public sources. It is not legal, architectural, engineering, or contractor advice. Always confirm your project with the authority having jurisdiction before beginning work.