Jumpstarting the Market for Accessory Dwelling Units: Lessons Learned from Portland, Seattle, and Vancouver
Authors: Karen Chapple, Jake Wegmann, Farzad Mashhood and Rebecca Coleman
Release Date: April 2017
Across the United States, communities are experiencing challenges in building the housing they need to maintain affordability and accommodate future growth. Accessory dwelling units (ADUs), or separate small dwellings embedded within single-family residential properties, are an effective solution due to their low cost and immediate feasibility, with homeowners building in their own backyards. In fact, California researchers suggest that such small-scale infill development could account for as much as half of new development capacity in coming decades. Many cities and states have recently passed legislation easing zoning and permitting regulations for ADUs, most notably Senate Bill 1069/Assembly Bill 2299 in California, signed into law on January 1, 2017.
Despite government attempts to reduce barriers, a widespread surge of ADU construction has not materialized. The ADU market remains stalled. To find out why, this study looks at three cities in the Pacific Northwest of the United States and Canada that have seen a spike in construction in recent years: Portland, Seattle, and Vancouver. Each city has adopted a set of zoning reforms, sometimes in combination with financial incentives and outreach programs, to spur ADU construction. Due to these changes as well as the acceleration of the housing crisis in each city, ADUs have begun blossoming.
- Small Houses, Big Impact: Accessory Dwelling Units in Underutilized Neighborhoods (Blog)
- More Homes, Less Land: Accelerating Accessory Dwelling Units - ULI Presentation (Slides)
- Accessory dwelling units: Housing shortage solution? (Video interview with KTVU Fox 2 News)