Portland, Oregon
Portland pioneered ADU-friendly rules — no owner-occupancy requirement, waived system development charges for many projects, and detached units allowed on most residential lots.
$150K–$220K
All-in build cost
construction, design, permits & fees
$1,700–$2,100
Monthly rent
one-bed comps nearby
2–4 mo
Permit timeline
typical city review window
up to 800 sq ft
Typical max size
detached new construction
Estimates from regional cost and rental data — not a quote or a permit decision.
For Portland ADU builders
Every homeowner searching "ADU cost in Portland" ends up on a page like this. Our early-access widget will give them the answer for their exact address on your site — and send you the lead. Founding builders get it first.
FAQ
Most detached ADU projects in Portland land between $150,000 and $220,000 all-in — construction, design, permits and fees. Garage conversions come in lower; high-end finishes and difficult lots push higher. These are estimates from regional cost data, not a quote.
Local comps put a new one-bedroom ADU in Portland at roughly $1,700–$2,100 per month, depending on neighborhood, size and finish.
Permit review in Portland typically runs 2–4 months, plus design time before you submit. Oregon state law requires cities to allow ADUs in residential zones, which keeps review predictable.
Portland pioneered ADU-friendly rules — no owner-occupancy requirement, waived system development charges for many projects, and detached units allowed on most residential lots. The fastest way to find out for a specific address is a feasibility check against the city's zoning data — that's exactly what our early-access widget will do on builders' websites.