ADUs are allowed in Lake OswegoTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Lake Oswego, OR
Is your property eligible for an ADU?
# of Properties
16,241
Owner-occupied
71%
Zoning districts
35
Avg Home Value
$1,164,671
Median Lot Size
0.21 acres
Avg Income
$154,121
Residential Types:
16,241 housing units
Single Family
81%
2-3 Family
1%
Apts (4+ units)
1%
Other
18%
Zoning Districts:
16,646 parcels · 35 districts
R-7.5
29%(4,764)
R-10
21%(3,526)
R-5
11%(1,863)
R-0
10%(1,703)
Other
29%(4,790)
ADU Rules
What can you build in Lake Oswego, OR?
Lake Oswego, 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 of gross floor area for an internal or attached ADU.
Detached ADU Size Limits
- –Maximum ADU size of 800 sq ft citywide
- –In R-7.5, R-10, R-15, R-6, R-5, and R-DD zones: if the detached ADU is 18 ft tall or less, the maximum is the lesser of 800 sq ft or the primary building’s footprint; if taller than 18 ft, the maximum is the lesser of 600 sq ft or the primary building’s footprint
Max Units
- –1 ADU per lot
Owner Occupancy
- –No owner-occupancy required.
Parking
- –No ADU parking minimum; no citywide maximum. If parking is provided, it may not be located in a required yard or special street setback; off-street space serving single-family/middle housing must be 8 ft 6 in wide by 18 ft 6 in long.
Rental Restrictions
- –Short-term rentals may not be marketed or used for group events.
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