One Step Closer to Lowering Barriers for ADUs – We Want Your Input!

Home » One Step Closer to Lowering Barriers for ADUs – We Want Your Input!

Housing affordability is one of the biggest issues we face in Seattle today. The City has identified a need for providing a mix of housing types at prices accessible to people at all levels of income for homeowners and renters alike. I believe lowering the barriers to creating accessory dwelling units (ADUs) is an important part of addressing affordability across the city. We’re beginning the environmental review process to analyze potential effects of encouraging more ADUs in Seattle, and we want your input.

Backyard cottages and in-law units can provide more affordable options for housing in neighborhoods where homes are often unaffordable to many people. ADUs are small, secondary dwelling units inside, attached to, or in the rear yard of a single-family house. A detached ADU (DADU), often called a “backyard cottage,” is a separate structure allowed in the rear yard of certain single-family-zoned lots. DADUs can be new structures or created through conversion of an existing structure, like a garage.

Seattle has relatively few backyard cottages right now. In May 2016, the Seattle City Council released a proposal to make it easier for homeowners to build backyard cottages and in-law units in Seattle and increase housing options for Seattle renters.

The initial analysis from the City’s Office of Planning and Community Development (OPCD) suggests that adding a backyard cottage on just five percent of eligible single-family lots could create about 4,000 new housing units.

Based on a decision from the City’s Hearing Examiner in December 2016, the City is preparing an Environmental Impact Statement (EIS) to review the potential environmental impacts of the proposal, which would:

  • allow an attached ADU and a backyard cottage on the same lot
  • remove the existing off-street parking and owner-occupancy requirements
  • change some development standards that regulate the size and location of backyard cottages

The EIS process includes several opportunities for community members to weigh in on the analysis, and I encourage you to do so. We will kick-off the EIS process with a 30-day scoping comment period beginning on October 2, 2017, and anticipate releasing the Draft EIS in spring 2018 and the Final EIS in summer 2018. The full timeline is available online.

Share your feedback!

The first phase of the EIS process is to determine the scope of the study, and the City wants your input on what to consider and analyze as we explore allowing more ADUs in Seattle’s neighborhoods.  During the scoping phase, you can help determine the alternatives the City will study, potential environmental impacts to consider, and possible measures to avoid or reduce the effects of the proposal.

DEADLINE:  Comments are due by 5:00 p.m. on November 1, 2017. You can share your input in several ways:

For more information, visit

What is an EIS? An EIS is a tool to inform decision making about the positive and negative effects of a proposal. The proposal might be a project, like construction of a new building or road, or a new policy or plan that could affect the environment. Washington’s State Environmental Policy Act (SEPA) requires Environmental Impact Statements so that the public, tribes, and other public agencies can help identify a proposal’s environmental impacts, as well as strategies for reducing or avoiding them. Decision-makers can then approve, modify, or deny the proposal as appropriate.