ADU Requirements around Portland Metro

Lately we've been branching out and providing ADU design outside of Portland. Since the requirements for ADU's can vary depending on your property's town or county, we decided to share these requirements in the list below.

Although there are many similarities with requirements for Accessory Dwelling Units in areas outside of Portland, Oregon (or even Washington and California) there are aspects of the general requirements that we also see vary by town or county jurisdiction.  What we've noticed that can change across jurisdictions are:

  • the size of ADU's (ex. 400-1000sf)
  • the types of ADU's allowed (ex. Detached, Attached, Basement, Garage..)
  • the number of bedrooms (ex. 1, 2, no limit)
  • and how ADU requirements vary within a jurisdiction by zone (ex. allowed, not allowed, 500sf max, 700sf max..) 

The common theme is that town planning departments and communities generally accept Accessory Dwelling Units, although they aim to "maintain the character" of the neighborhood, and this sets the setback(s) and/or limits the height so that the primary residence remains the dominant element present to the street. We also see some towns imposing different aesthetic requirements.

In order to help clarify all of these differences, please see our list below. While we're only covering a few of the towns outside Portland to the south and west, we hope to add more to this list over time, so if you would like us to look into and add your town to this list, please get in touch!

Accessory Dwelling Unit or ADU Requirements, by town:

Clackamas County ADU Requirements

Clackamas Maps

Clackamas County Zoning Map (PDF)

Clackamas County Zoning Code Table 315-1: What Zones are ADUs allowed in

Gladstone R-5 ADU Requirements

Gladstone R-7.2 ADU Requirements

Milwaukie ADU - Attached

Milwaukie ADU - Detached

Oregon City ADU Requirements

Tigard ADU Requirements

Portland ADU Requirements