Portland's ADU fee waiver (2010-2016)
Portland waived system development charges for ADUs starting in 2010, cutting the cost of adding a unit by thousands of dollars. Annual ADU permits rose from about 100 to more than 800 by 2016.
Portland became an early US leader in ADU construction, adding thousands of units.
The city reinstated some fees as the program matured, showing how financial incentives can be adjusted.
Portland shows how removing cost barriers changes construction volumes. Massachusetts is using a different lever: cheaper capital through state-backed loans.
