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 · Verified June 25, 2026 · Source
Effective Date
2019-08-08
Preempts Local Ordinances
Yes — state law overrides local restrictions
Has State Law
Yes
Statewide ADU Preemption Applies
State law establishes statewide preemption standards that supersede local regulations. The citation and source below confirm the verified legal basis.
Key Provisions
Eliminates single-family-only zoning in Oregon cities with population 10,000 or more — duplexes must be allowed by-right in single family residential zones · Source
Cities may not impose design standards that make middle housing effectively infeasible · Source
No owner-occupancy requirement allowed for ADUs in cities with population 10,000+ · Source
Local jurisdictions must adopt compliant code or be subject to state model code · Source
Oregon Land Conservation and Development Commission (LCDC) has enforcement authority · Source
Applies to all cities in Oregon's Urban Growth Boundaries (UGBs) · Source
Does not apply to rural communities or unincorporated areas below 10,000 population · Source
Legislative History
2019 — HB 2001 · Verified June 25, 2026 · Source
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. · Source
2021 — SB 458 · Verified June 25, 2026 · Source
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. · Source
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