Oregon ADU Laws & Rules (2026)

Compare ADU zoning rules across 4 Oregon cities. Average ADU score: 7.8/10.

Very ADU-FriendlyStatewide Legalization

Key Oregon ADU Laws

Key Oregon ADU Laws

  • Statewide legalization — ADUs allowed in all single-family zones (HB 2001)
  • No off-street parking required for ADUs
  • Two ADUs per lot allowed in many cities
  • Portland leads with streamlined permitting and pre-approved plans

Oregon Cities ADU Comparison

CityMax SizeSetbacksPermit FeesBuild Cost1BR RentScore
Bend 800 sq ft maximum floor area Per underlying zoning district; detached ADU must be at least 6 ft from the main house $1,700-$2,900 $140,000-$280,000 $1,300-$1,800/mo 7/10
Eugene 800 sq ft (or 10% of lot area, whichever is smaller) 10 feet $1,600-$2,700 $140,000-$280,000 $1,200-$1,700/mo 8/10
Portland 800 sq ft or 75% of primary (whichever is less) 5 feet ~$1,900 permit and plan review; plus System Development Charges (SDCs) of about $19,000 - see impact fees $150,000-$300,000 $1,400-$1,900/mo 9/10
Salem 900 sq ft (or 75% of the main building gross floor area, whichever is less) Confirm with Salem Planning (SRC 700.007) $1,800-$3,000 $130,000-$260,000 $1,100-$1,550/mo 7/10

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