ADUs offer a case study on the failure of well intentioned, half-hearted policies

A common theme throughout this week’s readings is a focus on the challenges and possible solutions to affordable housing availability.  Suggestions focus on actions government should take, including innovative land use and economic policy changes like restructuring funding structures for low-income housing developments, and restructuring public schools as ‘community service hubs’ (Wallace & Wells, 30) including building teacher’s dorms.   A number of the solutions are much less radical, however, and have been echoed for years among policy reformers and environmental activists.    These include; reducing or eliminate parking requirements (or garages for single family developments), streamlining permitting processes, and eliminating zoning barriers to ‘allow for diverse building types and techniques, including but not limited to group homes, micro-units, factory built housing, and ADUs’ (ULI 24).

Many of these policy changes represent relatively easy fixes that have thus remained incompletely implemented.  While I appreciate the broad number of solutions being offered by scholars and policy advisors, it may be worth asking why reduced parking requirements and ADUs have been so difficult to effectively implement.

ADU policies became widespread in municipalities throughout Puget Sound beginning in the mid 1990’s.  A number of analyses collected on by Alan Durning on Sightline Daily, a Cascadian blog focused on sustainability, highlights how utterly inept that these policy have been in the region, below the Canadian board that is.  Vancouver B.C. and its outlying suburbs are different story.  Though both Portland and Seattle have recently made moves to eliminate financial and bureaucratic barriers to ADU development, both the overall stock of ADUs and the rate of ADU permits remains below that of Vancouver.  Anecdotal analysis shows that in Portland only .3% of eligible single family lots have ADUs (Durning).  In Olympia the case is similar, with only about 1% of homes having ADUs., and Seattle is no better.  Contrast this with Vancouver, where some neighborhoods have about 50% of lots with ADUs, and some properties contain both attached and detached units.

The biggest barriers to ADU adoption appear to be parking requirements (some of which require driveway access), size limits, design requirements for style and location of an ADU entrance, and occupancy limits.  While one could devote volumes to politics and legal implication of each of these, they generally point to traditional fears about erosion of traditional suburban neighborhoods.  The result is a well-intentioned policy that completely contradicts itself.  Whether these disparities between Vancouver and cities below the boarder represent the result of some cultural difference, a legal peculiarity, or something else I can only speculate.  Study of the Vancouver B.C. metro area could offer guidance for effectively implementing these important policies.  Housing in the Pacific Northwest consists mostly of single family housing.  ADUs represent a real opportunity to not only address environmental issues related to housing, but can offer much needed financial help for home owners and help to equitably spread the burden of increased density.  Thus far they are an elusive dream

.ADU scores_Daily

(Chart courtesy of, )


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