Accessory Dwelling Unit (ADU)

Examples of Accessory Dwelling Units - Internal, Attached, and DetachedAn Accessory Dwelling Unit (ADU) is a residential dwelling unit located on the same lot as a single-family dwelling and is subject to square footage limitations. It is not a recreational vehicle. The habitable living unit provides basic living requirements including permanent cooking facilities.

ADUs tend to take one of 3 main forms:

  1. As an addition to an existing home
  2. As an internal conversion of living space in an existing home (e.g., a basement or attic)
  3. As a separate structure detached from an existing home on site.

Download the Guide to Accessory Dwelling Units in Oregon City (PDF) for more information!

ADU Alternatives

A habitable building without permanent cooking facilities would qualify for our Accessory Structures process.

Through our new Middle Housing Code, Oregon City now allows the construction of a detached duplex unit on a lot with an existing house that's at least five years old.

A "Tiny Home," which is typically mounted on a trailer or vehicle chassis, qualifies as a recreational vehicle. According to Oregon City Municode (OCMC) 12.16.040, Oregon City does not allow people to live in recreational vehicles. However, "Tiny Homes" that are built on permanent foundations and hook up to city services are permitted through the ADU process. Continue reading for more information.

ADU as a Short Term Rental

Can I offer an ADU as a Short-Term Rental? Short-Term Rentals that rent living space to customers for 30 days or less, like Airbnb and VRBO, are described in the Oregon City Municipal Code under the definition of "Bed and breakfast inns and boarding houses." Bed and Breakfast inns and boarding houses are only allowed in residential zones through a Type III Conditional Use Permit process.

ADU Application Review Criteria

The Planning Division reviews ADU applications for compliance with Oregon City Municipal Code.

Generally speaking, the following chapters of the code are directly applicable to all ADUs:

The property's underlying zone.

  • OCMC 17.14 - Single-Family Detached and Duplex Residential Design Standards
  • OCMC 17.20.010 - Accessory Dwelling Unit, Live/Work Dwelling, and Manufactured Home Park Design Standards
  • OCMC 17.54 - Supplemental Zoning Regulations and Exceptions

However, different properties have different characteristics, configurations, and dimensions. Depending on the circumstances, an ADU application might involve additional review if the ADU project requires a Variance or is located in:

Find Out More About Your Property

The City's website has a variety of resources available including Property Reports and Online Mapping System. You may also call the Planning Division at 503-722-3789 or email Planning for more information.

ADU Application Review Processes

  • Generally, the Planning Division reviews ADU applications through a Type I Land Use process that's integrated into the application packet attached at the bottom of this page. Type I applications involve a non-discretionary review process and are typically reviewed by staff within two weeks.
  • The Building Division and Public Works must also review an ADU project for compliance with the codes they oversee.
  • ADU projects that are in overlay districts or require a Variance are typically reviewed through a Type II Land Use Process (PDF) or Type III Land Use Process (PDF) that usually begins with a Pre-Application Conference.

How to Apply

If you have any questions about the Planning application process, you can email the Planning Division or call 503-722-3789.

ADU Planning Review Fees

Once we receive an ADU application, Planning Division staff must take time to review it to ensure the project complies with all relevant codes. The fees we charge are related to the time and effort typically required to review your project.

You can view our Planning Review of a Building Permit Fee and all other potential review processes that may affect an ADU project, on our Planning Fee Schedule.

System Development Charges (SDCs)

Oregon City's Public Works Department also reviews ADU applications and charges System Development Charges (SDCs) based on the expected impact of a new ADU development on public infrastructure. For any questions regarding SDCs, please email Public Works for more information.