Best adu — Portland, OR

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.

About this service

Defining the best unit for your property depends on your specific goals, such as maximizing rental yield or creating a versatile multi-generational living space. A great build features high-quality insulation, smart storage solutions, and an aesthetic that complements your main house. We emphasize durable construction and efficient design to ensure your unit remains a valuable asset for your property over the long term. Let us help you plan the right layout. Exact pricing confirmed free on the call.

Frequently asked in Portland

Also serving nearby: Vancouver · Beaverton · Gresham · Hillsboro · Salem

All cities in Oregon →

More on this: HUD ADU resources — ADU policy and financing research.

Service area details

Serving all of Portland — population 630,498; about 4,723 residents per square mile across 133.5 sq mi. ZIP codes covered include 97201, 97202, 97203, 97204, 97205, 97206, 97207, 97208.

Neighborhoods served in Portland: Alberta Arts District, Hawthorne District, Laurelhurst, Pearl District, Sellwood-Moreland, Woodstock — and every surrounding area.