Accessory Dwellings

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ADU Survey Report Published

A survey of ADU owners in Portland, Eugene, and Ashland, Oregon is complete and now published.  You can find it at Oregon DEQ’s website and  This mail and web survey was administered by Portland State University’s Survey Research Lab and developed by the Oregon Department of Environmental Quality, Portland Metro’s regional government (Metro), and

ADU survey coverThe purpose of the survey was to gain a better understanding of how ADUs are being used, who is using them, the financing mechanisms for them, and some energy and structural characteristics of them.  The survey included questions about past, current, and future ADU use; current occupant demographics and rental logistics; construction; energy use; and owner demographics.  A total of 860 ADUs owned by 839 owners were surveyed.  Of those 860 records, 698 were from Portland, 104 from Eugene, and 67 from Ashland.  Overall, 68% of the ADU records were identified as “owner occupied” – where the owner was living in either the main house or the ADU.  Response rates averaged among the 3 cities totaled 44.6%, which was quite good for a mailed survey.  The sample targets were met for Portland and the 3 cities combined and the sampling error was less than 5%, which means the results can be used reliably to reflect on the Portland ADU population and the 3 cities combined.

Results for the combined cities indicate:

  • 80% of ADUs are being used as someone’s primary residence
  • 40% of the ADU occupants range in age from 25-34 years old, which was the largest age range reported
  • 58% of the occupants were female and 42% male
  • 81% of ADU occupants own 1 or more cars
  • 75% of ADU owners charge rent to their occupants
  • Average monthly rent charged was $850
  • 10% of ADU owners exchange services (e.g. childcare) for all or part of the rent
  • Average construction costs were $81,000
  • Average square footage of the ADU is 668 sq ft.
  • 50% of ADU owners are male / 50% female
  • Average age of an ADU owner is 53 years old

Most of the statistics above are very similar when just looking at the city of Portland, which contributed to 78% of the combined cities sample.

At the most basic level, the driving purpose of the survey was to understand how ADUs are being used.  This survey confirms that 80% of ADUs are, in fact, being used as primary residences, which helps support future policy efforts to encourage ADU development.  Please check out the report for much more detailed information.

Finally, the report communicates the summized data of the resondents and doesn’t offer any interpretation.  Oregon DEQ and partners may continue to analyze the data in the future to offer further interpretation.  If you are interested in further analyzing the raw data results, please contact Jordan Palmeri at Oregon DEQ ( and share your ideas on how this data can be used here at the blog.

[update summer 2014: a new paper has been published that uses this survey’s data to examine eight policy questions. — ed.]


This entry was posted on October 4, 2013 by in News, Policy & Trends and tagged , , , , .
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