ADU Permits: Gresham vs Portland
How do adu permits rules compare between Gresham, OR and Portland, OR?
Gresham, OR
Multnomah County
No data available yet for Gresham.
Portland, OR
Multnomah County
Portland allows ADUs by-right in all residential zones under Portland City Code Title 33 (Zoning Code) Chapter 33.205. Up to two ADUs are permitted per single-family lot under Oregon HB 2001 and Portland's Residential Infill Project (RIP). Building permits from the Bureau of Development Services (BDS) are required, with streamlined ADU review and pre-approved plans available.
View full Portland rules →Key Facts Comparison
| Fact | Gresham | Portland |
|---|---|---|
| Code Section | - | PCC Title 33 Chapter 33.205 |
| ADUs Per Lot | - | Up to 2 |
| Max Size | - | 800 sq ft or 75% of main |
| Max Height | - | 20 ft detached |
| Permit Authority | - | Portland BDS |
Highlighted rows indicate differences between cities.
Gresham FAQ
No FAQs available.
Portland FAQ
How many ADUs can I have on a Portland lot?
Up to two ADUs per single-family lot under Oregon HB 2001 and the Portland Residential Infill Project. Common combinations include one basement conversion plus one detached backyard cottage, or one attached plus one detached.
What is the maximum size of a Portland ADU?
800 square feet or 75 percent of the principal dwelling's floor area, whichever is less, under Portland City Code Title 33.205. Detached ADUs cannot exceed 20 feet in height.
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