Oregon

Oregon's HB 2001 eliminated single-family-only zoning statewide, making it one of the most ADU-friendly states in the country. Portland has been a national leader in ADU construction for over a decade. ADU Pass helps Oregon homeowners cut through the permit paperwork and take advantage of the state's progressive housing policies.

525 ZIP codes
37 Counties
337 Cities

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State ADU details

State ADU law

Oregon has the most comprehensive statewide ADU preemption framework in the country after California. House Bill 2001 (2019), codified principally at ORS 197.312(5), requires every Oregon city of more than 2,500 residents inside an urban growth boundary, and every Oregon county with population over 15,000, to allow at least one accessory dwelling unit (interior, attached, or detached) by right for each existing or newly-constructed single-family detached dwelling on residentially-zoned lots. Local jurisdictions may impose 'reasonable regulations' on siting and design but may NOT require owner-occupancy of either the primary or accessory unit and may NOT require additional off-street parking. Senate Bill 458 (2021), codified at ORS 92.031, authorizes 'middle housing land divisions' that allow each unit of a duplex / triplex / quadplex / townhouse / cottage cluster to be partitioned onto its own lot for fee-simple sale via an expedited land-division process; SB 458 does not directly add an ADU mandate but interacts with HB 2001 because an existing ADU can be split off onto its own lot under SB 458's expedited process (although a new ADU cannot be created after a SB 458 division). HB 2001 also separately preempts single-family-only zoning in cities over 25,000 by mandating duplexes statewide (and triplexes, quadplexes, townhouses, and cottage clusters in larger cities), which is the 'middle housing' provision discussed alongside ADUs in DLCD guidance.

Statutes:

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State insurance regimes

Oregon operates the Oregon FAIR Plan Association, the state's residual property-insurance market for fire-and-extended-coverage perils. The plan is administered by a non-profit association of admitted insurers and serves as the insurer of last resort for properties unable to obtain coverage in the voluntary market. Oregon's wildfire-driven insurance market has been the focus of major recent state action: SB 762 (2021) appropriated $220M+ for wildfire mitigation and authorized the Department of Forestry to publish the Oregon Wildfire Hazard Map; SB 82 (2023) prohibits insurers from using any state wildfire risk map as the sole basis for cancellation, non-renewal, or premium increase, and requires insurers who do cancel / non-renew on wildfire grounds to disclose the property-level information used and the available mitigation measures. The Oregon Division of Financial Regulation (DFR), within the Department of Consumer and Business Services, regulates rates and forms.

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State housing programs

Oregon's state-level ADU policy infrastructure is concentrated in the Department of Land Conservation and Development (DLCD), which publishes guidance documents for cities and counties implementing ORS 197.312(5) and ORS 197.758, runs the Housing Choice and Middle Housing technical-assistance programs, and audits municipal compliance with HB 2001. Oregon does not currently maintain a statewide pre-approved ADU plan catalog (those exist at the city level, e.g. Portland's pre-approved ADU plans), and there is no statewide impact-fee waiver, no statewide streamlined-review timeline floor beyond the reasonable-regulation requirement of ORS 197.312(5), and no state ADU rebate program.

  • DLCD ADU implementation guidance — Statewide guidance to local governments on what 'reasonable regulations' on ADU siting and design under ORS 197.312(5) means in practice. Updated September 2019 to coincide with HB 2001 enactment.
  • DLCD Housing Choice / Middle Housing technical assistance — Ongoing TA program that supports cities and counties in updating development regulations to comply with HB 2001 (ADUs and middle housing) and SB 458 (middle housing land divisions).
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Known state issues (2)

  • policy-review (since 2022-06) — The Oregon Wildfire Hazard Map (originating in SB 762 of 2021) has been republished multiple times since 2022; SB 82 (2023) decoupled the map from insurance underwriting. Insurance availability and pricing for ADUs in wildland-urban-interface counties (Jackson, Josephine, Klamath, Deschutes, Hood River, etc.) remains volatile in the voluntary market; the Oregon FAIR Plan is the residual market. (source)
  • policy-review (since 2020-01) — Some Oregon municipalities adopted post-HB 2001 ordinances that DLCD or third-party advocates contend impose unreasonable siting and design conditions on ADUs. Litigation and Land Use Board of Appeals decisions continue to refine what 'reasonable regulations' means under ORS 197.312(5); the League of Oregon Cities tracks these decisions. (source)
Federal (United States) — ADU-relevant rules and programs

Federal ADU law

The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.

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Federal financing programs

Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.

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Federal tax credits

There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.

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Federal housing programs

HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.

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