Understanding Portland’s Middle Housing and RIP2

What Is "Middle Housing"?

Middle housing refers to modest-scale, multi-unit homes that bridge the gap between single-family homes and larger apartment complexes. This includes duplexes, triplexes, fourplexes, attached houses (like townhomes), accessory dwelling units (ADUs), and cottage clusters. These housing types are embedded in neighborhoods without altering their overall character—an approach often dubbed “gentle density.”

The Residential Infill Project (RIP)—Phase 1 & 2

• RIP1 (Phase 1) went into effect in August 2021 and allowed duplexes, triplexes, fourplexes, affordable sixplexes, and expanded ADUs in R2.5, R5, and R7 zones—areas previously restricted to single-family homes.
• RIP2 (Phase 2) became effective on June 30, 2022. It completed the expansion of middle housing allowances to larger-lot zones (R10, R20), introduced cottage clusters and attached houses across all residential zones, and streamlined the process for middle housing land divisions—enabling each unit to have its own lot. It also brought Portland in line with statewide mandates HB 2001 and SB 458.

Policy Drivers: Oregon’s HB 2001 & SB 458

• HB 2001 (2019) mandates that cities allow duplexes, triplexes, fourplexes, and cottage clusters on single-family-zoned land.
• SB 458 further requires that each middle housing unit can exist on its own parcel (land division).
• RIP2 aligns Portland's zoning rules with these state laws.

How Has Middle Housing Performed?

Production & Location

• Between August 2021 and mid-2024, Portland permitted over 1,400 ADUs and middle housing units in single-dwelling zones.
• By 2023-2024, middle housing accounted for 23% of new units citywide in single-dwelling zones; by mid-2024, that number rose to 43%.
• Production has focused near “centers and corridors”—well-served areas with amenities, jobs, and transit.

Affordability & Market Impact

• Newly built middle housing generally costs $250K–$300K less than new single-detached homes, with much of that difference driven by smaller size.
• Units supported by Portland Housing Bureau affordable homeownership programs can be priced around $500K less than new single-family homes.

Land Efficiency & Design

• In its first year, middle housing comprised 73% of units permitted in R2.5, R5, and R7 zones, mostly as fourplexes.
• Middle housing produced far more units per lot compared to single-family construction—3.4 vs. 1.2 units per lot.
• Most middle housing units feature 2+ bedrooms, with 24% including 3+ bedrooms—great for families or multi-generational households.
• By mid-2024, demolitions remained stable, but the ratio of units built per unit demolished increased significantly.

Why RIP2 Matters

• Equity & Ownership: Expanding housing options—especially affordable ones—in traditionally exclusive single-family neighborhoods opens doors for broader ownership and access to amenities.
• Inclusive, Subtle Growth: Provides more housing without skyscrapers or sprawl; supports gentle infill that blends into existing neighborhoods.
• Efficiency: Makes better use of urban land, aligning with Oregon’s Urban Growth Boundary, reducing pressure to expand outward.
• Policy Model: Portland demonstrates how cities can implement smart zoning reforms within existing legal frameworks to make progress on housing access.

Challenges & Considerations

• Uneven Access: Some areas (like the “Z” overlay zones in the West Hills) restrict middle housing due to wildfire concerns, impacting over 24,000 lots. Such overlays risk undermining RIP2’s intent.
• Barriers for Homeowners: Many homeowners may lack resources or expertise to pursue middle housing development, potentially ceding opportunities to developers. Stakeholders call for financial incentives, technical assistance, and tools to support equitable outcomes.

Summary Table

Phase

Key Features

Zones Affected

RIP1 (2021)

Introduced middle housing + ADUs

R2.5, R5, R7

RIP2 (2022)

Added R10/R20, cottage clusters, land division, state compliance

R10, R20, plus all zones

Result

Outcome

Housing Growth

Middle housing surged to 43% of new units in single-dwelling areas

Affordability

Lower cost housing ($250K–$300K savings); $500K less via affordable programs

Land Efficiency

More units per lot; minimal increase in demolitions

Access & Design

More diverse options—cottage clusters, ADUs, multi-gen homes

Equity Concerns

Certain overlays and cost barriers may hinder equitable access

Final Thoughts

Portland’s RIP2 reflects a thoughtful, data-driven approach to tackling housing challenges—expanding access, preserving neighborhood scale, and encouraging equitable ownership. While hurdles like regulatory overlays and adoption barriers persist, RIP’s trajectory underscores the power of zoning reform as a tool for inclusive, sustainable urban growth.

Questions? Reach out.