ADUs are allowed in SeasideTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Seaside, OR
Is your property eligible for an ADU?
# of Properties
4,216
Owner-occupied
38%
Zoning districts
37
Median Lot Size
0.11 acres
Avg Income
$52,149
Residential Types:
4,216 housing units
Single Family
6%
2-3 Family
4%
Apts (4+ units)
2%
Other
88%
Zoning Districts:
6,524 parcels · 37 districts
R2
33%(2,144)
R3
16%(1,057)
C3
8%(541)
RR
7%(448)
Other
36%(2,334)
ADU Rules
What can you build in Seaside, OR?
Seaside, 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
- –By-right maximum size for an internal/attached ADU: 525 sq ft
- –Maximum size for an internal/attached ADU with Conditional Use approval: 800 sq ft
Detached ADU Size Limits
- –Maximum floor area for a detached ADU (backyard cottage) of 525 sq ft by right
- –Maximum floor area for a detached ADU (backyard cottage) of 800 sq ft with Planning Commission Conditional Use approval
Parking
- –1 space per ADU (in addition to 2 spaces for the primary dwelling); no max specified; ADU space must be accessible without moving vehicles in the other two spaces; off-street parking for dwellings must be on the same lot as the dwelling
Rental Restrictions
- –Short-term rentals (<30 days) prohibited for both detached and internal ADUs; ADUs cannot be used as Vacation Rental Dwellings (VRD) defined as rentals of less than 30 days.
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.
Clatsop County