Portland’s official ADU guide describes a local process for a new accessory dwelling unit or a conversion of an attic, basement, or garage to habitable space. A building permit is required for that work. Electrical, plumbing, and mechanical permits may also be needed and can be filed with the building application or later. Confirm the exact permit set for the property and scope before applying.
Prepare for the site and application review
Before submission, Portland directs applicants to check permit history, zoning, utilities, hazards, and applicable construction standards. A site condition may call for a separate report or review. Prepare the site plan, drawings, application information, and supporting materials required for the project; the City’s linked forms and current requirements control.
Applications are submitted through the City’s online process. Track the permit status through Portland’s permit-search tools. If reviewers need more information or corrections, the City sends a checksheet; respond to each item and resubmit the requested information. Review can continue through correction rounds, so a complete initial package does not establish when a permit will be issued.
Pay the final fee and complete inspections
Portland says the permit is not issued until all final fees are paid. Building-permit charges depend on permit type, the proposed work’s valuation, and staff review. Trade permits, utility or service changes, and system development charges are separate items to check; the ADU guide does not give a complete fee total or a project-specific review duration.
After issuance, use the inspection card to identify the likely inspection stages and arrange each inspection through the City’s process. Portland states that every permit needs a final approval inspection to be complete. An inspection report may identify lack of access, incomplete work, or code violations that need to be addressed before approval.
Keep each approval and final record
Planning or zoning, building, trade, utility, hazard, and other reviews answer different questions. A building permit or inspection result does not decide every land-use or private-restriction issue. Retain the permit, approved drawings, correction responses, inspection results, and final approval record. For a general application and closeout checklist, see plans, inspections, and completion documents.
The City guide does not state an ADU-specific processing-time guarantee. Ask the current Portland authority about the permit category, applicable fees, required inspections, and open conditions for the property before using any expected date or cost.