Oregon Zoning — The First State to End Single-Family Zoning
Data version: Q2 2026 · Last updated 2026-05-13
TL;DR. Oregon is a pioneer in American zoning reform. In 2019, HB 2001 made Oregon the first state to effectively end single-family-only zoning, requiring cities to allow duplexes, triplexes, and fourplexes on residential lots. ADUs are allowed statewide with no owner-occupancy or parking requirements. Portland has gone further with the Residential Infill Project allowing up to 4 units on most lots. Buildability™ analyzes all Oregon-specific factors.
HB 2001: ending single-family zoning
Oregon HB 2001 (2019) requires: cities over 25,000 to allow fourplexes on all residential lots, cities over 10,000 to allow duplexes. Cities cannot use design review, parking requirements, or lot size minimums to effectively block middle housing. This was the first such statewide law in the U.S. and dramatically expanded buildability on residential lots.
Statewide ADU rights
Oregon requires all cities with populations over 2,500 to allow ADUs on residential lots. Local jurisdictions cannot require owner occupancy or off-street parking for ADUs. No limit on short-term rental of ADUs. Size, height, and setback standards vary by city but cannot be used to effectively prohibit ADUs. Oregon is one of the best states in the nation for ADU investment.
Urban growth boundaries
Oregon requires every city to establish an Urban Growth Boundary (UGB) that separates urban land from rural/farm land. Development is concentrated inside UGBs and severely restricted outside them. This makes location relative to the UGB the single most important factor for Oregon buildability. Buildability™ identifies UGB status for all Oregon properties.
Major Oregon markets
Portland (640K, Residential Infill Project allows 4 units, 6-16 week permits), Salem (180K, middle housing implementation), Eugene (175K, sustainability-focused infill), Bend (105K, fastest-growing, UGB expansion). Common OR zones: R5, R7, R10, R20, CM, CG, EG. Median home: $490K. Permit timeline: 3-16 weeks.
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