Zoning, building permits and septic rules in Portland, Oregon

Portland’s own rules

• Building permitRequired

  One- and two-family homes inside Portland city

  • Threshold applies to structures more than 200 sq ft or taller than 15 ft.
  • If the parcel is over 2 acres and the structure is at least 20 feet from property lines and other structures, a permit is required when the building area is over 400 square feet.
  • Different rules apply to three or more units.

  area threshold: > 200 sq ft (400 sq ft on parcels over 2 acres with 20 ft separation)

  “build, demolish or move any structure that is more than 200 square feet in area or has a height of more than 15 feet measured from the grade plane to the average height of the highest roof surface.”

• Local zoningPresent

  Land inside Portland city limits

  • Zoning code is Title 33, Planning and Zoning; chapter 33.110 covers single-dwelling zones.

  “single dwelling zones (rf, r20, r10, r7, r5, r2.5) generally developed with detached single-family residences and some attached single-family residences and duplexes zoning code chapter 33.110 single-dwelling residential zones”

• Zoning districtsPublished

  Base zones inside Portland city

  • Single-dwelling zones are RF, R20, R10, R7, R5, R2.5; multi-dwelling, commercial/mixed use, employment/industrial and campus institutional zones also exist.

  “there are five categories of base zones: single-dwelling residential zones multi-dwelling residential zones commercial or mixed use zones employment and industrial zones campus institutional zones”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Portland or Multnomah County directly.

• Owner-builder exemption — Owner-builder inside Portland city
• Building code adopted — Building code inside Portland city
• Inspections — Inspections inside Portland city
• Certificate of occupancy — Occupancy certificates inside Portland city
• Minimum dwelling size — Single-dwelling zones inside Portland city

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.