ADU Laws in Oregon (2026)
Oregon state ADU law details, key provisions, preemption status, and recent legislative changes for accessory dwelling units.
Law Name
Oregon House Bill 2001 (HB 2001) — Middle Housing in Medium and Large Cities
Effective Date
2019-08-08
Preempts Local Ordinances
Yes — state law overrides local restrictions
Has State Law
Yes
Key Provisions
Eliminates single-family-only zoning in Oregon cities with population 10,000 or more — duplexes must be allowed by-right in all residential zones
Cities with population 25,000 or more must allow middle housing (duplexes, triplexes, fourplexes, cottage clusters, townhomes) by-right in all residential zones
Cities may not impose design standards that make middle housing effectively infeasible
No owner-occupancy requirement allowed for ADUs in cities with population 10,000+
Local jurisdictions must adopt compliant code or be subject to state model code
Oregon Land Conservation and Development Commission (LCDC) has enforcement authority
Applies to all cities in Oregon's Urban Growth Boundaries (UGBs)
Does not apply to rural communities or unincorporated areas below 10,000 population
Legislative History
2019 — HB 2001
Landmark legislation eliminating single-family-only zoning in Oregon cities 10,000+ population. Required duplexes by-right in cities 10,000+ and middle housing (triplex, fourplex, cottage cluster, townhome) by-right in cities 25,000+. Effective August 8, 2019. Local compliance required by June 30, 2021.
2021 — SB 458
Senate Bill 458 (effective July 1, 2022) requires cities to allow lot splits for middle housing development. Cities 10,000+ must allow splitting lots developed with middle housing into separate parcels for individual unit ownership. Enables condo-style ownership of middle housing units created under HB 2001.
2023 — HB 3414
House Bill 3414 clarified HB 2001 compliance requirements and reinforced LCDC enforcement authority over non-compliant jurisdictions. Required additional cities to update their development codes to fully implement middle housing requirements.
Official Sources
What Does Preemption Mean for Local Cities?
Because Oregon law preempts local ordinances, individual cities cannot impose restrictions stricter than the state standard. A city may still have additional administrative requirements, but cannot deny ADU applications that comply with state minimums.
Learn about Oregonzoning preemption →Source: Oregon House Bill 2001 (HB 2001) — Middle Housing in Medium and Large Cities. Last verified April 5, 2026. View source