Portland Accessory Dwelling Unit Guide
Data version: Q2 2026 · Last updated 2026-05-13
Buildability City Score™: B+ (Top 35%) · Median permit time: 75 days
TL;DR. Find out if your Portland property qualifies for an accessory dwelling unit. Buildability™ checks the local ADU ordinance, Oregon state law, your zoning district, lot size, setbacks, parking requirements, and owner-occupancy rules in about 20 seconds. Free for your first check.
Portland ADU rules at a glance
Portland follows local ordinances layered on top of Oregon state ADU law. Typical restrictions cover maximum size (often 800–1,200 sqft), height (16–25 feet), side setbacks (4 feet minimum in most jurisdictions), parking (often waived near transit), and owner-occupancy. Buildability™ reads Portland's specific code against your exact lot.
Why this matters
Most Portland homeowners don't discover their ADU is infeasible until they've spent $3,000+ on preliminary design. Buildability™ catches the blockers first — easements, overlays, wetland proximity, utility extension costs — so you don't waste soft costs on a dead-end project.
How Buildability™ checks your Portland property
Enter any Portland address. Buildability™ pulls zoning, lot dimensions, easements, environmental overlays, utility access, and current Oregon state ADU law. Results include your Buildability Score™, setback envelope, maximum ADU size, parking waiver eligibility, and an estimated permit timeline — in about 20 seconds. Free for your first check.
Help us keep this accurate
Buildability™ translates Portland's ADU rules in plain language. Rules change and overlays are sometimes missed — if you spot an error on this page, email team@buildability.us with the URL and what's off. We verify with the Portland planning department and update within 48 hours of a confirmed correction. Portland planning staff: the same email works if you'd like to flag corrections or set up a direct verification channel.
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