City of Portland ADU Permit Trends

The City of Portland continues to grow its ADU housing stock.  In 2013, there were almost 200 ADU permit applications received, which is about 25% of all single-dwelling permits in Portland.  In total, there are approximately 800 completed and permitted ADUs in Portland.   The chart shows the dramatic impact of the 2010 waiver of System Development Charges (SDCs), which reduces the cost of building an ADU by $8,000-11,000. 

In 2010, the ADU zoning code was also changed to allow ADUs to be built up to 75% the size of the main house, or 800 sqft feet – whichever is smaller.  The old size limit was 33% the size of the main unit, which was considerably more restrictive.  We anticipate that the increased interest in ADUs will continue since the SDC waiver was recently extended until July 2016, and knowledge about ADUs grows among Portland residents.