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Residential Infill Project (RIP and RIP2) and New Development Projects

Learn more about the Residential Infill Project and schedule a meeting to discuss the related zoning code that went into effect Aug. 1, 2021, and was updated on June 30, 2022 (RIP2). Find information about what the Residential Infill Project means for development projects.
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The City of Portland adopted rules that govern the types of housing permitted in our neighborhoods. The changes allow more housing options in Portland’s neighborhoods. This includes more accessory dwelling units (ADUs), duplexes, triplexes and fourplexes, and a new development option called cottage clusters.  The Residential Infill Project also adopted limits on the size and scale of residential development.

Residential Infill Project code changes give homeowners more options 

Residential Infill Project code changes began on Aug. 1, 2021. Additional code changes took effect with Residential Infill Project – Part 2 (RIP2) on June 30, 2022. With the changes, homeowners and developers have a lot more options to add more units to a property or lot. This project is intended to

  • Expand what you can do in "single-family" zones.
  • Make more accessible and less expensive housing available.

More flexibility for how you use lots

In zones R2.5, R5, R7, R10 and R20, the Residential Infill Project adds a lot of flexibility to build, including:

  • An increase in the number of units you can build on each lot
  • An increase in the number of allowable configurations on lots
  • Removal of the off-street parking requirement in single-dwelling zones
  • A new development called cottage clusters

Limits to building size

A requirement to measure each building’s floor area ratio on the lot limits the size of buildings. Read more about floor area ratio and how it might affect your project and understanding floor area in single-dwelling zones.

Find out if your lot can have more units

The z overlay map shows where more Residential Infill Project housing types are not allowed. Lots in the z overlay have flooding, landslide, or wildfire hazards, have environmental zoning, or wildfire hazard. See Portland City Code 33.418, Constrained Sites Overlay Zone for a complete list of the constraints that trigger application of the z overlay. The z overlay is shown on the zoning map.

Why you can't add units to some lots

A duplex is allowed on all single-dwelling zoned lots where a primary structure is allowed, with the exception of the RF (Residential Farm Forest) zone.

However, you cannot build additional units, beyond a duplex, on some lots, such as lots on unmaintained streets, unless they have frontage on a dedicated pedestrian or bike connection that leads to a maintained street.

Minimum lot size requirements

The minimum lot size for most housing options is shown below:

  • Zone R2.5: 1,500 square feet
  • Zone R5: 3,000 square feet
  • Zone R7: 4,200 square feet
  • Zone R10: 6,000 square feet
  • Zone R20: 12,000 square feet

Cottage Cluster development

A new development option called cottage cluster is allowed in most zones that allow residential development. Cottage clusters are groups of relatively small homes oriented around a shared common space such as a courtyard or garden.

A cottage cluster is defined as a group of no fewer than three detached dwelling units and no more than 16 units on one lot. per acre with a footprint of less than 900 square feet each that includes a common courtyard. Cottage clusters are allowed in the RM1, R2.5, R5, R7, and R10 zones (see Zoning Code sections 33.110.265.G and 33.120.270.G).

Visitability requirements

For new construction with three or more units on the site, including ADUs, one building must be visitable. Visitability standards include: 

  • A no-step, barrier-free main entrance
  • A bathroom and small living area accessible to the main entrance
  • 32-inch-wide internal doors between the entrance, the bathroom and the living area for wheelchair accessibility

Attached houses

Attached houses are individual units on their own lots that are attached to another house along a common property line. Attached houses have been allowed in single-dwelling zones for decades, but RIP2 changes the density calculations so they are allowed at roughly the same density as a triplex or fourplex.

Lots for these higher density attached houses are created through a standard land division process and must meet the street frontage and other applicable land division criteria.

Because they are allowed at a higher density, ADUs are not allowed with attached houses on lots below a certain minimum size.

For lot size and density allowances for attached housing, see Zoning Code Sections 33.610 and 33.611.

Land divisions for middle housing

A middle housing land division will allow certain specific development types (e.g. a duplex or triplex) to be divided into separate lots at the same time that building permits under review for the development. Middle Housing Land Divisions are processed through an expedited process and are subject to clear and objective standards. Learn more about Middle Housing Land Divisions and how they apply to certain types of residential developments.

Get answers to questions about the Residential Infill Project: talk with an expert

We can answer questions about the new rules. You can set up a 15-minute appointment with a city planner or call the General Inquiries phone number to discuss your questions. Or, set up an Early Assistance meeting for a deeper discussion about the Residential Infill options (including RIP2).

More information about recent zoning changes

For more information about recent zoning code changes and how they affect certain types of residential development, please visit the web pages for each of these legislative planning projects:


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