ADUs are allowed in GreshamTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Gresham, OR
Is your property eligible for an ADU?
# of Properties
28,029
Owner-occupied
78%
Zoning districts
39
Avg Home Value
$239,305
Median Lot Size
0.17 acres
Avg Income
$92,867
Residential Types:
28,029 housing units
Single Family
84%
Other
16%
Zoning Districts:
30,888 parcels · 39 districts
LDR-5
42%(12,882)
LDR-7
28%(8,557)
CMF
6%(1,904)
TLDR
3%(1,053)
Other
21%(6,492)
ADU Rules
What can you build in Gresham, OR?
Gresham, 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 900 sq ft for an ADU that is internal to or attached to the primary dwelling, including one built over a garage.
Detached ADU Size Limits
- –Maximum size is 750 sq ft; outside DCC, DMU, DTM, DRL-1, DRL-2, and CNRM it is further capped at 50% of the primary home's habitable (occupiable) floor area, whichever is less.
Max Units
- –1 ADU per existing primary single detached dwelling on the lot; 1 ADU per existing primary townhouse on the lot.
Parking
- –0 spaces minimum; no maximum; off-street parking must comply with Section 9.0800 design standards; no ADU-specific parking standards; accessible spaces only if triggered by Building Code.
Rental Restrictions
- –Short-term rentals prohibited for ADUs (detached and attached).
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.
Multnomah County