Accessory Structures in Oregon (2026)
62 rules on the books across Oregon, 17 cities and counties. Select a rule to read the full details.
Severity: Few Restrictions · Light Restrictions · Some Restrictions · Significant Restrictions · Heavy Restrictions
ADU Rules
Rules for building accessory dwelling units (granny flats, in-law suites) including size limits, parking requirements, and owner-occupancy rules.
Oregon: statewide
StatewideFew RestrictionsUnder ORS 197A.425, Oregon cities over 2,500 population and counties over 15,000 must allow at least one accessory…
Read full rule →Beaverton
Some RestrictionsBeaverton allows one accessory dwelling unit per single-detached home through a staff-level Type 1 permit, capped at…
Read full rule →Benton County
Some RestrictionsIn unincorporated Benton County, an accessory dwelling unit is allowed only where zoning permits it inside an urban…
Read full rule →Clackamas County
Some RestrictionsIn unincorporated Clackamas County, ZDO Section 839 allows one ADU per single-family dwelling. Inside an urban growth…
Read full rule →Corvallis
Some RestrictionsCorvallis allows one accessory dwelling unit per lot under Land Development Code Section 4.9.40, capping ADU floor area…
Read full rule →Eugene
Some RestrictionsEugene allows one accessory dwelling per lot in every residential zone under EC 9.2751(17), capping an attached ADU at…
Read full rule →Gresham
Some RestrictionsGresham allows one Accessory Dwelling per single detached dwelling, capped at 900 square feet or 75 percent of the…
Read full rule →Hillsboro
Some RestrictionsHillsboro allows one accessory dwelling unit per single detached dwelling or townhouse, sized between 250 and 750…
Read full rule →Josephine County
Some RestrictionsIn rural Josephine County's Rural Residential zones (RR-1, RR-2.5, RR-5), a homeowner may build one accessory dwelling…
Read full rule →Lane County
Some RestrictionsLane County allows one accessory dwelling unit per lot in the Rural Residential zone under Lane Code section 16.290(8)…
Read full rule →Medford
Some RestrictionsMedford allows one ADU per single-family, duplex or townhouse lot, capped at 900 square feet or 75 percent of the…
Read full rule →Multnomah County
Some RestrictionsIn the Rural Residential zone, unincorporated Multnomah County allows one accessory dwelling unit per single-family…
Read full rule →Portland
Some RestrictionsPortland caps accessory dwelling units at 800 square feet or 75% of the primary home's living area, whichever is…
Read full rule →Salem
Some RestrictionsSalem caps an accessory dwelling unit at 900 square feet or 75 percent of the main house's gross floor area, whichever…
Read full rule →Springfield
Some RestrictionsIn the City of Springfield, Oregon, Development Code section 3.2.275 lets a homeowner add an accessory dwelling unit by…
Read full rule →Tigard
Some RestrictionsIn the City of Tigard, Oregon, a lot with small form residential development can add one detached accessory dwelling…
Read full rule →Washington County
Some RestrictionsWashington County allows up to two Urban Accessory Dwelling Units on a single-family lot in the unincorporated urban…
Read full rule →Marion County
Few RestrictionsOregon law requires Marion County and its cities to allow at least one accessory dwelling unit (ADU) for each detached…
Read full rule →ADU Impact Fees
Impact fees, school fees, utility hookup charges, and waivers for ADUs. Many jurisdictions exempt ADUs under 750 sq ft from impact fees per state law.
Clackamas County
Some RestrictionsAccessory dwelling units in unincorporated Clackamas County are not exempt from the county's Transportation System…
Read full rule →Lane County
Some RestrictionsLane County charges its Parks and Recreation System Development Charge on every new dwelling built in the…
Read full rule →Medford
Light RestrictionsMedford cuts a homeowner's Street System Development Charge in half for an accessory dwelling unit of 900 square feet…
Read full rule →Tigard
Light RestrictionsIn the City of Tigard, Oregon, an accessory dwelling unit of 1,000 square feet or less that complies with TMC 3.24.180…
Read full rule →Salem
Few RestrictionsSalem charges system development charges (SDCs), its impact fees for water, wastewater, stormwater, transportation, and…
Read full rule →ADU Owner Occupancy
Whether the property owner must live on-site to operate an ADU, deed-restriction requirements, and recent state-law changes lifting owner-occupancy rules.
ADU Rental Restrictions
Whether an ADU can be rented short-term (Airbnb), 30-day minimums, separate rental licenses, and long-term lease requirements.
Benton County
Heavy RestrictionsOnce a property in unincorporated Benton County has an accessory dwelling unit, neither the ADU nor the primary house…
Read full rule →Gresham
Heavy RestrictionsGresham's Development Code flatly bars Accessory Dwellings from being used as short-term rentals, closing off a popular…
Read full rule →Josephine County
Significant RestrictionsIn Rural Residential zones outside the Grants Pass and Cave Junction urban growth boundaries, § 19.61.020(B)(8) of the…
Read full rule →Medford
Significant RestrictionsAn ADU that gets Medford's 50% Street SDC exemption cannot be rented short-term for 10 years afterward. The restriction…
Read full rule →Multnomah County
Significant RestrictionsMultnomah County bars short-term rental of accessory dwelling units in rural residential zones like MUA-20 outside…
Read full rule →Salem
Significant RestrictionsSalem bars accessory dwelling units from operating as short-term rentals or accessory short-term rentals. The rule sits…
Read full rule →Washington County
Significant RestrictionsRural accessory dwelling units in unincorporated Washington County cannot be rented out as vacation rentals. CDC §§…
Read full rule →Tigard
Some RestrictionsIn the City of Tigard, Oregon, an ADU that receives the SDC exemption cannot be used as a short-term rental for 10…
Read full rule →Shed & Carport Rules
When a storage shed or carport needs a permit, the square-footage exemption thresholds, and the setback and height limits that apply either way.
Beaverton
Some RestrictionsBeaverton caps combined accessory-structure footprint at 500 square feet on lots up to 10,000 square feet (700 on…
Read full rule →Benton County
Some RestrictionsIn the Rural Residential zone of unincorporated Benton County, BCC § 63.405(5) lets a shed or other non-residential…
Read full rule →Clackamas County
Some RestrictionsIn unincorporated Clackamas County, ZDO Section 315 sets accessory-building setbacks. A shed behind the building line…
Read full rule →Corvallis
Some RestrictionsIn the City of Corvallis, a shed counts as an Accessory Structure, and Land Development Code Section 4.3.40 names sheds…
Read full rule →Eugene
Some RestrictionsEugene caps accessory buildings, sheds, detached garages and workshops, at 10 percent of the lot area under EC…
Read full rule →Gresham
Some RestrictionsGresham's Development Code sets sliding setbacks for backyard sheds and other detached accessory structures based on…
Read full rule →Hillsboro
Some RestrictionsBackyard sheds, detached garages and other accessory structures in Hillsboro follow Community Development Code §…
Read full rule →Josephine County
Some RestrictionsIn rural Josephine County, outside the Grants Pass and Cave Junction urban growth boundaries, the combined footprint of…
Read full rule →Lane County
Some RestrictionsSheds, garages, greenhouses and other accessory structures are a permitted use on rural residential (RR) land in…
Read full rule →Marion County
Some RestrictionsA carport is a residential accessory structure in Marion County. Its peak height is nine feet at the lot line…
Read full rule →Multnomah County
Some RestrictionsIn unincorporated Multnomah County's LR-5 residential zone, a detached carport must sit behind the house's rear line or…
Read full rule →Portland
Some RestrictionsPortland caps detached sheds and other covered accessory structures at 20 feet tall, holds them to standard building…
Read full rule →Salem
Some RestrictionsIn Salem's RS single family zone, a shed or other accessory structure must sit at least 5 ft from an interior side…
Read full rule →Springfield
Some RestrictionsIn the City of Springfield, Oregon, Springfield Development Code section 4.7.360 caps an accessory structure such as a…
Read full rule →Tigard
Some RestrictionsIn the City of Tigard, Oregon, an accessory structure on a small form residential lot is limited to 528 square feet on…
Read full rule →Washington County
Some RestrictionsDetached sheds and other residential accessory buildings in unincorporated Washington County can't cover more than 25%…
Read full rule →Garage Conversions
Rules for converting a garage into living space, including whether you need to replace the lost parking and what building codes apply.
Beaverton
Some RestrictionsConverting a garage into an accessory dwelling unit is allowed in Beaverton, but unlike a basement or attic conversion…
Read full rule →Hillsboro
Some RestrictionsHillsboro lets a homeowner convert an existing garage into an accessory dwelling unit under Community Development Code…
Read full rule →Marion County
Some RestrictionsIn Marion County, an attached garage converted to living space is treated as part of the dwelling and must meet the…
Read full rule →Medford
Some RestrictionsMedford values a garage conversion to habitable space at 50 percent of the "R-3 Residential" rate on the ICC Building…
Read full rule →Springfield
Some RestrictionsIn the City of Springfield, Oregon, Development Code section 3.2.275(B)(1) lets a homeowner convert a garage into an…
Read full rule →Tigard
Some RestrictionsIn the City of Tigard, Oregon, a detached garage can be turned into a detached accessory dwelling unit, but the 800…
Read full rule →Washington County
Some RestrictionsConverting an attached garage into an accessory dwelling unit is the one case in Washington County's ADU code where the…
Read full rule →Tiny Homes
Zoning rules for tiny houses on wheels and foundations, including minimum square footage requirements and where they can be placed.
Oregon: statewide
StatewideFew RestrictionsOregon requires every city over 2,500 people and every county over 15,000 to allow at least one accessory dwelling unit…
Read full rule →Beaverton
Significant RestrictionsBeaverton has not adopted Appendix Q's special tiny-house standards, so a tiny house here must meet the same full…
Read full rule →Benton County
Significant RestrictionsBenton County will not issue a building permit for a tiny house on wheels, classified as a Group R-5 wheeled…
Read full rule →Josephine County
Significant RestrictionsIn unincorporated Josephine County, a small ancillary living unit is permitted only as a "detached living space" under…
Read full rule →Multnomah County
Significant RestrictionsIn Multnomah County's Multiple Use Agriculture (MUA-20) zone, an accessory dwelling unit must be a permanent structure…
Read full rule →Lane County
Some RestrictionsA tiny house on a permanent foundation is treated as a dwelling or ADU under Lane Code 16.290 and must meet building…
Read full rule →Marion County
Some RestrictionsMarion County has no tiny-home-specific ordinance. A permanent tiny house on a foundation is regulated as a dwelling or…
Read full rule →