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Oregon Statewide Rule

Oregon Statewide Accessory Dwelling Unit Mandate

Few RestrictionsApplies statewide across Oregon (2026)

Key Facts

City threshold
Population over 2,500
Units required
At least one ADU
Owner occupancy
Cannot be required
Authorizing statute
ORS 197A.425 (formerly 197.312)
Origin bill
SB 1051 (2017)
Last verified: September 5, 2026Source: Oregon Public Law

Summary

Under ORS 197A.425, Oregon cities over 2,500 population and counties over 15,000 must allow at least one accessory dwelling unit on each single-family lot inside urban growth boundaries, subject only to reasonable siting and design standards.

197A.425 Accessory dwelling units. (1)(a) A city with a population greater than 2,500 or a county with a population greater than 15,000 shall allow in areas within the urban growth boundary that are zoned for detached single-unit dwellings the development of at least one accessory dwelling unit for each detached single-unit dwelling, subject to reasonable local regulations relating to siting and design. (b) As used in this subsection: (A) "Accessory dwelling unit" means an interior, attached or detached residential structure that is used in connection with or that is accessory to a single-unit dwelling. (B) "Reasonable local regulations relating to siting and design" does not include owner-occupancy requirements of either the primary or accessory structure or requirements to construct additional off-street parking. (2) Subsection (1) of this section does not prohibit local governments from regulating vacation occupancies, as defined in ORS 90.100, to require owner-occupancy or off-street parking. [Formerly subsections (5) and (6) of 197.312; 2025 c.38 §25] 197A.430 Single room occupancies.

Source: Oregon Public LawView official code

Full Breakdown

Oregon Senate Bill 1051 (2017), now codified at ORS 197A.425 after the 2023 land-use recodification, requires local governments to permit accessory dwelling units on single-family residential lots within urban growth boundaries. Cities cannot ban ADUs outright, require owner occupancy, or mandate off-street parking, and may impose only reasonable building, dimensional, and design standards. House Bill 2001 (2019) separately expanded duplex and middle-housing requirements in larger cities. Local jurisdictions retain authority over specific height, setback, and design standards within these state-imposed limits.

Violations & Penalties

Local ordinances that ban ADUs or impose unreasonable restrictions are unenforceable. Owners may challenge them at the Land Use Board of Appeals under ORS 197.825.

Frequently Asked Questions

Can my Oregon city ban ADUs?
No. Cities over 2,500 population and qualifying counties must allow at least one ADU per single-family lot inside urban growth boundaries. Outright bans violate ORS 197A.425.
Can a city require me to live on the property?
No. Owner-occupancy requirements for ADUs are prohibited under state law. Cities may still regulate setbacks, height, parking, and design within reasonable limits.
Does the ADU mandate apply outside city limits?
It applies in counties over 15,000 population within urban growth boundaries. Rural resource-zoned land follows separate Oregon land-use rules.

Sources

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