Residential Infill Project

From HousingWiki
Portland's Residential Infill Project

known locally as RIP, this is an initiative of City of Portland, Bureau of Planning and Sustainability (BPS) begun in 2015 to write new zoning rules for single-family residential neighborhoods all over the city.  As of summer 2019, BPS has grouped it into the Housing_Opportunity_Initiative along with several Better Housing by Design Project, and the Anti-displacement Action Plan.

Current draft (Feb 2019 Revised).

Twitter research search link, suggeested hashtag: #PDXRIP.


from Residential Infill Project Summary: Recommended Draft" (August 2019). 

"In order to meet the demands of our growing city and ensure that future generations of Portlanders can live and thrive here, we need to take advantage of our entire housing area.  Single-family zones make up 43% of our housing land supply while multi-dwelling zones cover 8%. Our single-family neighborhoods can provide housing options that improve the quality of life for current and future residents – our teachers, bus drivers, retail clerks, construction workers and students. We believe that RIP is one tool to achieve that vision. The Residential Infill Project has been amended by the Planning and Sustainability Commission to deliver even more smaller scale, less expensive housing in Portland’s single-family neighborhoods. By offering homeowners and home builders the opportunity to create up to four units on a single-dwelling lot (at a smaller scale and height than is currently allowed), the Residential Infill Project allows the return of attractive, popular and more affordable middle housing types to Portland’s residential neighborhoods.


One piece of the larger housing affordability puzzle
City and regional leaders are addressing the housing crisis on many other fronts, including:

  • A $258 million affordable housing bond passed on the November 2016 ballot that will create 1,300 newly affordable homes over the next several years.
  • Newly created revenue streams for affordable housing, such as the construction excise tax and the accessory short-term rental fund.
  • Affordable housing incentives for multi-family housing projects through the MULTE program.
  • A collaborative effort to address homelessness through the Joint Office of Homeless Services by connecting thousands of people with housing, employment, health and emergency services.
  • An inclusionary housing program that requires affordable housing units in new multi-family residential development and provides additional incentives for creating affordable housing units.
  • New tenant protections, including relocation costs for no-cause evictions or large rent increases.


Projected impact

Johnson Economics study: 24,000 new infill homes viable

Johnson Economics. "Economic Analysis of Proposed Changes to the Infill Development Standards." November 29.

Summarized by BPS in [Tracy 2018]:

"The economic analysis is based on a predictive model that looks at the real market value of parcels against a series of housing prototype proformas to determine the relative likelihood that a parcel will develop. For example, when the real market value (RMV) of a parcel is less than the residual land value (RLV) of a development type, then that parcel is assumed to develop."  [Tracy 2018]

BPS internal analysis: 4,000 of projected 123k new homes by 2035 would occur as infill 

based on Comprehensive Plan assumption of 123k new housing units by 20135

"Portland planners started with the assumption that the city would add about 123,000 housing units by 2035 -- a number already vetted and used in the city’s comprehensive zoning plan. Most of those are projected to be built in high-density areas like downtown or busy commuter corridors. Portland’s single-family neighborhoods would get 16,000 new units, according to the comprehensive plan. "With the adoption of the infill proposal, planners shifted some growth from apartments along corridors into single-family neighborhoods. They now project about 20,000 new households in residential neighborhoods – a 4,000-home net increase in those areas. "The planning bureau considers the 4,000 tally a “more realistic view” of projected infill growth, said Oliveira, the spokesman, though planners say the differing forecasts are intended to complement rather than compete against one another. “They’re both valid in terms of providing a range of what the outcomes could be,” said Tyler Bump, a senior economic planner for the city.  [Schmidt & Njus 2019]

Comment: In other words, the city internal report started from a fixed figure for expected household growth, based on the Buildable Lands Inventory the city is required to do under state land-use law. They then considered how many of the expected 20,000 new households might move into RIP infill units, rather than homes in other areas (i.e. high-density central-city and commuter corridor areas). 


Antidisplacement / Displacement effects

The February 2019 "Revised Draft" of RIP included a new section "Appendix H: Displacement Risk and Mitigation" [Feb 2019b]. \

From Executive Summary: 

"The Comprehensive Plan calls upon new plans to evaluate the potential to cause displacement or
increase housing costs in vulnerable communities. Part I examines who is vulnerable to indirect
displacement and where redevelopment is most likely to happen under the proposal. Overall, the
proposal is likely to reduce displacement of low-income renters in single-family homes across
This reduction results from allowing more units to be built on one lot, which means fewer lots
will be redeveloped across the city. However, Brentwood-Darlington, Lents, and parts of the Montavilla
neighborhood east of 82nd Avenue are likely to see significant increases in redevelopment that could
lead to the increased displacement of vulnerable households

"The proposal will likely significantly reduce the cost of housing for the additional housing types allowed in single-dwelling zones. This is a function of the smaller unit sizes as well as the ability to defray land costs across two, three, or four housing units as opposed to one unit. These findings suggest the proposals will reduce displacement citywide, increase housing supply, create less-expensive housing options, and provide choices for types of housing that were historically allowed but have since been disallowed in Portland’s single-dwelling zones. This, in turn, gives more people across wider range of the
income and racial spectrum the opportunities and benefits afforded by our great neighborhoods.

"The Comprehensive Plan also calls for identification and implementation of strategies to mitigate for anticipated impacts. Part II presents an array of potential strategies to mitigate displacement among vulnerable residents in Portland’s single-dwelling neighborhoods. Where program funding is available for anti-displacement and community stabilization in single-dwelling zones, the neighborhoods most at risk of displacement should be the focus for these actions. "Strategies for vulnerable renters include education, financial assistance, incentives to property owners to keep rent affordable, and expanded homeownership opportunities. "Strategies for vulnerable homeowners include education to combat predatory practices, financial assistance to stabilize homeowners, and technical assistance and financing to enable low- and moderate-income homeowners to take advantage of the expanded housing choices allowed by the proposal."

Some people [e.g. the Oregonian articles noted] have raised a question: if the city's estimate of 4,000 additional infill homes is too low, and the real infill figure is higher, along the lines of the Johnson Economics study of 24,000 net change, what does this mean for projected displacement, could that be higher? 

In response, RIP supporters say we should compare the 24,000-new-homes scenario to a scenario with similarly high demand but the status quo zoning. In this case, displacement would be significantly higher. 

Fine-tuning the incentives

RIP is notable for the careful analyses made around it regarding how program details might nudge outcomes one way or another. 

[Andersen 2018] noted a comment of a Planning and Sustainability Commission member: 
Cap building sizes, but let them get slightly bigger for each additional home they create

"In a series of straw votes Tuesday, the commission endorsed a set of policy changes designed to stop the gradual mansionization of Portland by capping the size of new homes, re-legalizing structures that include more than one home inside and—crucially—allowing buildings to get slightly bigger (about 500 square feet on most lots) for:

  • each additional home;
  • creating homes affordable to lower-income households; or
  • saving and lightly modifying an older structure as part of internally dividing it into multiple homes.

This crucial final part of the proposal, intended to give owners a reason (other than the goodness of their hearts) to create more and cheaper homes when they redevelop their property, had been recommended in May by numerous housing advocates."