The City’s new Comprehensive Plan encourages more housing choices throughout the city to accommodate a greater range of family sizes, incomes and ages, as well as the changing needs of households over time. A diverse supply of housing helps to create diverse communities and opportunities for households to remain in their neighborhoods as their lifestyles and housing needs change over time, especially for older adults seeking to age within their communities.

Single houses on individual lots make up more than half of the city's housing stock. Code changes to allow and encourage more housing types in Portland’s single-dwelling zones and other areas are key to increasing housing supply that is affordable to a broad spectrum of households.

The new Comprehensive Plan encourages relatively smaller and more affordable housing near Centers and Corridors and within Inner Ring neighborhoods. Additional study of service availability and infrastructure capacity is needed prior to adopting new housing type exceptions in Portland’s single-dwelling zones.

What is currently allowed

A house may currently have a single Accessory Dwelling Unit (ADU) that is up to 75 percent the size of the primary house and a maximum of 800 square feet. ADUs can be created from a converted basement or attic, added on to an existing house or built as a separate detached structure. Additionally, duplexes (two units on a single lot) or attached houses (two units, each on its own lot, sharing a common wall on the property line) may be built on corners and on lots bordering commercial zoned lots. In the R2.5 zone, duplexes and attached houses are allowed on any lot that is at least 5,000 square feet in size.

Proposal: Allow more units within the same form as a house near Centers and Corridors.

  • Allow two ADUs per house – one internal to the house and one detached
  • Allow one accessory dwelling unit (ADU) with a duplex
  • Allow duplexes on all lots and triplexes on corner lots
  • Allow an additional bonus unit for providing an affordable unit, an accessible unit or internally converting an existing house to multiple units

Number of units within proposed housing forms graphic. This depicts housing types and number of units that are currently beyond what is allowed in Portland's single-dwelling zones: House with 2 ADUs, Duplex, Duplex with detached ADU, Triplex on corner.

Proposal: Allow cottage clusters on lots larger than 10,000 square feet.

  • Develop specific cottage cluster rules to augment Planned Development review
  • Speed up review process by reducing review procedure from Type III to Type IIx (more information on review procedures available here)
  • Allow additional bonus units for providing affordable units, accessible units or for retaining the existing house on the site

Proposal: Establish a minimum unit requirement for all R2.5 zone lots.

  • Require one unit per 2,500 square feet of site area
  • Allow ADUs to count toward the minimum requirement

Download the Residential Infill Project draft proposal booklet.