ADUs are allowed in Oregon CityTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Oregon City, OR
Is your property eligible for an ADU?
# of Properties
12,416
Owner-occupied
71%
Zoning districts
21
Avg Home Value
$768,477
Median Lot Size
0.19 acres
Avg Income
$106,678
Residential Types:
12,416 housing units
Single Family
92%
2-3 Family
2%
Apts (4+ units)
2%
Other
4%
Zoning Districts:
12,860 parcels · 21 districts
R8
27%(3,430)
R10
26%(3,354)
R6
23%(2,919)
R3.5
10%(1,280)
Other
15%(1,877)
ADU Rules
What can you build in Oregon City, OR?
Oregon City, OR follows state and local rules for Accessory Dwelling Units. Here is a concise overview of the local rules.
Eligibility
- –Internal / Attached ADU: By Right
- –Detached ADU: By Right
Interior / Attached ADU Size Limits
- –Maximum size of 800 sq ft; basement conversions without new floor area are exempt.
- –Maximum size of 60% of the principal dwelling’s gross floor area; basement conversions without new floor area are exempt.
Detached ADU Size Limits
- –Maximum detached ADU size is the lesser of 800 sq ft or 60% of the principal dwelling’s gross floor area.
Max Units
- –1 ADU per detached single-family unit.
- –Cottage clusters: 0 ADUs.
- –R-2: existing SFD units constructed prior to the effective date: 1 ADU per detached unit when allowed.
Parking
- –0 spaces minimum; no ADU-specific maximum; multi-unit-on-one-lot exemption; other citywide waivers (transit, size, Regional Center) are redundant
ADU State Law
What can you build in Oregon?
- –In urban growth areas, Oregon law requires cities and counties to allow at least one ADU on lots zoned for detached single-family homes.
- –Local jurisdictions cannot require owner occupancy for ADUs, but may regulate short-term or vacation rentals.
- –There are no statewide limits on ADU size, height, setbacks, lot size, or floor area ratio. Local zoning rules apply.
- –Parking requirements, if any, are set by the local jurisdiction, subject to state limitations.
- –Some cities may allow more than one ADU per lot, depending on local code.
- –Oregon law does not require counties to allow ADUs in rural residential zones. Whether an ADU is allowed depends on county zoning.
- –ADUs in rural residential areas cannot be used for short-term or vacation rentals.
- –Additional requirements may apply related to wildfire risk, water supply, septic capacity, and fire access.
- –Counties may impose additional restrictions beyond state law or choose not to allow ADUs at all.
- –If a county allows ADUs, state law imposes strict limits, including a minimum 2-acre lot size, a maximum ADU size of 900 sq ft, a location within 100 ft of the primary dwelling, and a limit of one ADU per parcel.
What's allowed on your lot?
These are the municipality-wide rules. What's allowed on a specific property also depends on state laws, setbacks, floor area ratio, lot coverage, environmental constraints, topography, and other property-specific factors. Search your address on FutureLot to see what's allowed on your property.
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ADU rules in other Oregon municipalities
Rules change at the town line. Check the municipality your property is actually in.
Clackamas County