Portland Bureau of Development Services

You will find City of Portland’s information on this page about adding an accessory dwelling unit to a property.


Accessory Dwelling Unit (ADU) Finance Guide

A snapshot of some of the ADU financing options available in the Portland, Oregon metro area.


Kol Peterson, Backdoor Revolution: The Definitive Guide to ADU Development (2018)

Accessory Dwelling Units are a form of residential infill housing that are poised to revolutionize housing in the United States. Unlike other urban development trends, this one is being driven by homeowners, not professional developers. Through case studies, expert interviews, firsthand anecdotes, images, and data analysis, Backdoor Revolution reveals the opportunities, challenges, and best practices of ADU development for homeowners, including costs, financing, design, zoning barriers, and regulatory loopholes. With sections written for policymakers and small housing advocates, Backdoor Revolution offers insightful analysis and a succinct prescription for solutions to municipal and institutional barriers for ADU development.

Purchase here.

Budget Breakdown: A Portland Couple Design and Build a Compact Home For $222K

An architect and construction engineer couple build a sustainable, 624-square-foot abode for $221,580—here's how the numbers add up.



Your online resource for accessory dwelling units.


Accessory Dwelling Units in Portland, Oregon

Descriptive statistics of a survey of ADU owners, residents, and owners who live in an ADU.

New York Times article about ADUs in Portland, Grandma Never Had It So Good (2014)

“Thanks to zoning laws in Portland, Ore., that encourage putting a second living space on a single-family lot, [property owners] were able to transform their 480-square-foot garage into a home and rent out their four-bedroom house — an arrangement that pays for all their living expenses, and then some.”


Irvington English Cottage — Blog

Documenting the renovation of an 1929 "English Cottage"-style house located in the Irvington Historic District in Portland.