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ADU Eligibility Score

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What is an ADU Eligibility Score™ (AES)?
All residential lots in the City of Portland are zoned to allow accessory dwellings units, as of right. That said, some lots have better ADU potential than others. The AES is a benchmarking tool to aid homebuyers in the purchasing process by providing a quick sense of how much relative potential the site has for ADU development in terms of ease and cost of development.

The AES provides a ranking on three criteria about the property:

• Detached ADU Potential
• Internal Conversion Potential
• Cost Scale for Potential Internal Conversion

This tool can be used to assist homebuyers in determining whether and how an ADU can be developed on a given property.

Please note: this service is only available for properties within the Portland city limits.

How does an AES add value to my property?

If you are selling your property, you can attract buyers who are looking for ADU potential by offering the AES as part of your home's marketing plan. AES will provide 3rd party validation of the ADU potential of a property which will optimally help properties sell quicker when listed, or for higher values.

What does an AES include?
The AES includes a 1-page feasibility report with a ranking 1-10, 1 being low potential and 10 being high potential for ADU.


How does the evaluation work?

Kol will review the potential ADU components on the property and will provide a score based on the home's potential for a detached ADU or an internal conversion ADU, as well as the cost scale to do the project. For example, the garage is often a decent candidate for conversion due to its size, location, and new siding and roof, but there are possible foundation issues and potential issues with rotting and framing along the south wall. The evaluation will provide an overview of the opportunity and will help determine any barriers for an ADU project.

Is Portland permitting more ADUs?


Kol Peterson is an ADU expert based in Portland, Oregon, who has helped catalyze the exponential growth of ADUs in Portland over the last decade through ADU advocacy, education, consulting, policy work, and entrepreneurship. He is the author of Backdoor Revolution-The Definitive Guide to ADUDevelopment. He is the owner of Caravan- The Tiny House Hotel, the first tiny house hotel in the world, and organizer of Portland’s popular ADU Tour. He consults with homeowners about ADUs on their property, and teaches ADU classes for homeowners and for real estate agents in Oregon, Washington, and California. He edits and manages,,, and

Kol developed and lived in a detached new construction ADU in 2011, and developed a basement/garage conversion ADU in 2018. He has a masters degree in environmental planning from Harvard’s Graduate School of Design. Prior to his ADU work, Kol worked in the federal government for ten years in Washington, DC and Portland, Oregon.

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ADU Eligibility Score appointment- $250

*This service is only available for properties within the Portland city limits

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