Op-Ed: Seattle Merely 'Inching Forward' on ADUs

Earlier this month, Natalie Bicknell writes, Seattle released an environmental impact statement proposing the removal of code barriers to the construction of accessory dwelling units (ADUs) and detached dwelling units (DADUs). "The EIS also proposed size restrictions on construction of new single-family homes. Taken together, the two measures are intended to increase and preserve affordable housing stock throughout the city."

While the measure improves on the city's current policies, Bicknell says it does not favorably compare "to Portland's Residential Infill Project, or the more liberal ADU policies of Vancouver." She cites Dan Bertolet's point-by-point rundown of the Seattle plan's strengths and weaknesses, which include a wild card: a so-called "McMansion ban" on new homes that occupy too much of their lots.

Under the new rules, "new homes could be constructed at a maximum of 2,500 square feet or a floor-area ratio of 0.5, or no more the half the square footage of the lot. Considering that in 2018 the average size of a new single-family home in US is 2,641 square feet, with many new homes exceeding that size, the restriction does represent an improvement."

Portland's size restrictions went further, however, also legalizing housing types like duplexes and corner lot duplexes. In other words, missing middle housing.

See also: Portland Makes ADU Incentives Permanent