HomePlan

Phase 0 · Feasibility · Step 0.1

Confirm a DADU is allowed on your lot

Pull your parcel up on Portland Maps and check the zone, the base allowances, and any overlay that limits accessory structures. About a minute of work, and it tells you whether to keep going.

Who
Homeowner, PP&D
How long
1 day
Cost
Free
You end up with
Portland Maps zoning report (PDF or screenshot)

If you skip this: A handful of lots sit in an Environmental Conservation overlay (Title 33.430) or a landslide-hazard zone where a DADU may not be feasible at all. Portland Maps surfaces this in a minute, so you find out before paying for design.

Where the rules live

Portland Permitting & Development (PP&D, formerly BDS) runs the zoning code under City Code Title 33. The chapter that matters here is Title 33.205, the accessory-dwelling-unit chapter — it tells you whether a DADU is allowed on your lot, and at what size.

You don't have to start in the code, though. The city's free per-address tool, Portland Maps, gives you the zone, every overlay touching your parcel, and links straight to the relevant code sections.

The four things Portland Maps tells you

  1. Base zone. Most R zones (R20, R10, R7, R5, R2.5, RF) allow at least one ADU. Since the 2021 Residential Infill Project (RIP) reform, many lots that used to allow one ADU now allow two (one attached, one detached) or even a triplex/fourplex.
  2. Overlay zones. "Environmental" (e/p/c) overlays mean Title 33.430 review — that adds months and can kill the project entirely. Historic-resource overlays add design review.
  3. Hazard zones. Landslide (Title 24) and floodplain (Title 24 / FEMA) mapping add geotech requirements or rule out certain footprints.
  4. Lot dimensions. Setbacks (typically 5 ft side and rear for accessory structures), lot-coverage caps, and the 800 sq ft DADU max in most zones decide whether a usable cottage actually fits.

How to do it

  1. Open portlandmaps.com.
  2. Search your address.
  3. Open the Zoning tab and the Hazards tab. Save or print both as PDF.
  4. If anything on the overlay or hazard list is unfamiliar, click through to the matching Title 33 chapter.

What this step does not answer

Portland Maps confirms zoning. It doesn't tell you the utilities can serve the lot (that's 0.2 and 0.3), the trees can stay (0.4), or your specific design will pass review. Those come next.

Where this information came from

← Back to project map