With new ADU rules in effect, Seattle hopes to drop more barriers to building

The Seattle Office of Planning and Community Development (OPCD) is exploring its options for pre-approved accessory dwelling unit (ADU) plans, hoping to make them easier to build.

Back in July, the Seattle City Council passed long-awaited reforms to laws governing ADUs, which include backyard cottages and mother-in-law apartments. The legislation allows more (and bigger) ADUs to be built, and loosens some code requirements—for example, it axed a requirement for onsite parking, which was a difficult and sometimes-expensive requirement to comply with.

Since ADUs are, largely, something that would be built by a typical homeowner, not a developer, getting them built is somewhat of a challenge. Not only is the budget likely to be smaller—permitting fees could add up to thousands of dollars—but the paperwork is a pretty onerous thing for a non-professional to handle. Approval can take a few months or the better part of a year, depending on the circumstance, and it only gets more difficult and costly if plans are rejected and need to be resubmitted.

A quick process contributes to reduced fees—and other expenses, like design costs, could also go down. OPCD spokesperson Jason Kelly tells us that pre-approved plans cut review time, “both reducing cost of permit review and providing more certainty to the homeowner that projects will be approved.”

While the idea of pre-approved plans had been floated occasionally in the five years reforms were in effect, Seattle Mayor Jenny Durkan got the ball officially rolling; after signing the bill, her office issued an executive order directing various city agencies to work on making these projects more feasible, including pre-approving building plans. Other directives include a low-interest financing pilot, a new city position dedicated to helping homeowners navigate the process, and an ADU working group.

OPCD is working with builders, architects, and designers on what the plans could look like, but is also taking public feedback through a survey. Many architects and builders have stock and prefab plans for ADUs already in place—builder Node already has multiple lines of cottages, for example. Some firms have even developed a specialty around ADUs, building deep portfolios in recent years.

Designs from Microhouse, Best Practice, Cast Architecture, and Live-Work-Play are all used as illustrative examples in the city’s survey. Users are asked to rate design-review kinds of elements of the homes—massing, roof shape, window style—and then rate what’s important in ADU design, like architectural diversity and accessibility.

Kelly says that the city isn’t working with any specific architects on pre-approved plans at this point, but can provide details when submissions start. The jury reviewing plans, said Kelly, will include members of the Seattle Design Commission, Planning Commission, and Construction Codes Advisory Board, as well as representatives of design review boards. “They will have expertise to look at all aspects of the submitted plans,” says Kelly.

Matt Hutchins, a principal with Cast Architecture, says that not all architects are happy about the process. “There is a raging debate amongst residential architects about how this somehow devalues our work,” Hutchins writes to us over email.

“I’m not worried that trying to solve this will somehow devalue my work,” says Hutchins, who has been a longtime advocate for ADUs as a means for helping Seattle’s housing crisis, both individually and as a member of More Options for Accessory Residences (MOAR). “On the contrary, it is a chance to shine and do some good, which is great for the profession. Hopefully my peers will see the value as well.”

The original version of this article reported that the Seattle Department of Construction and Inspections (SDCI) is leading the project and that one ADU design in the survey was by Model Remodel. It has been corrected to reflect that it’s OPCD and Live-Work-Play, respectively.