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The City of Portland, Oregon

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Phone: 503-823-7300


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New Accessory Structure Zoning Code Regulations

City of Portland, Bureau of Development Services

On Wednesday, December 2, 2015, Portland City Council approved changes to City of Portland Title 33, Portland Zoning Code as part of the Bureau of Planning and Sustainability Regulatory Improvement Program, Accessory Structures Project.

The Accessory Structures Zoning Code Update project revises the regulations for accessory structures with a focus on detached accessory structures, such as garages, covered patios, storage sheds and accessory dwelling units (ADUs), as well as, decks, trellises, ADA ramps and mechanical equipment. The amendments streamline the standards to create one set of regulations for all covered accessory structures that is based more on form (setbacks, height and bulk) rather than function (how the building is used).

Summary of Accessory Structure Zoning Code Regulations

Summary of Accessory Structure Zoning Code Regulation Changes                                           

Major Changes effective January 4, 2016:

  • Accessory Structure Types Allowed in Setbacks. The Zoning Code currently allows detached garages to be built within required side and rear building setbacks as long as they meet specific size, height, and setback requirements.  These parameters will remain largely the same, but any kind of accessory structure (including ADUs) may use the provisions to be built within the setback.

  • Height Requirements Outside of Setbacks. When detached accessory structures are not located within required setbacks, the maximum height for these structures is 20 feet measured to the average height of the highest gable.  The Zoning Code currently allows ADUs to be 18 feet high, but other detached accessory structures to be the height limit of the zone (usually 30 feet).

  • Design Standards for Tall Accessory Structures and Increased Design Flexibility. The additional design standards (including matching roof pitch, exterior materials and windows) that apply to new ADUs will apply to all detached accessory structures, but only if they are over 15 feet tall.  No additional design standards apply to smaller structures.  The design standards required have been made more flexible and now allow options.

  • Mechanical Equipment in Setbacks. Mechanical equipment attached to the side of a building is allowed a 20 percent projection into a required side or rear setback.  Ground mounted mechanical equipment is allowed a full projection into side and rear setbacks, but screening with a fence or landscaping is also required.

For a complete list of changes and details about the Accessory Structure Zoning Code Update, please see the Accessory Structures Zoning Code Update draft.


Questions about impact of these changes on a development project?  Please contact BDS’s Planning and Zoning Hotline at 503-823-7526.