Seattle Unveils Pre-Approved Plans for Backyard Cottages Which Lowers Fees and Permitting Time

City launches ADUniverse website features step-by-step instructions for homeowners, accessible in dozens of languages

Seattle (September 15, 2020) – Mayor Jenny A. Durkan announced today, the launch of a new website called ADUniverse that features backyard cottage designs that have been granted pre-approved  City permits. The website includes a step-by-step guide to adding an accessory dwelling unit (ADU) on a property and new data about the implementation of this increasingly popular housing option. 

After signing into law the most progressive ADU ordinance of any major U.S. city last year, Mayor Durkan directed City agencies to identify strategies to reduce permitting times and costs for homeowners seeking to build ADUs on their property. In addition to providing an easily accessible design option, the pre-approved designs will shorten the permitting process by at least 2-6 weeks and save homeowners about $1,500 in permit fees. 

“While in the middle of global health pandemic, we are even more aware that we continue to face an affordability and housing crisis. It’s our responsibility to use every tool available to increase housing options in every part of our City. While the City expects to build more than 6,600 new affordable homes by 2023, we need to ensure we have range of housing options for everyone,” said Mayor Durkan. “These new designs will help streamline permitting issues, allow homeowners to provide alternative housing choices to renters within their communities, and create options for residents to age in place or live with loved ones.” 

The new ADUniverse website helps homeowners determine whether their lots may be suitable for an ADU and how large a cottage they could build. Currently the site offers a look at seven pre-permitted cottages ready for construction; up to three more designs will be available in the coming weeks. All architectural plans — ranging from a studio under 300 square feet to a 1,000-square-foot two-bedroom — will be available direct from the designer for $1,000 or less. Cottage designs have been reviewed against codes for the structure and its energy use; however, homeowners remain responsible for permits and inspections related to zoning, site preparation and the foundation, utility connections, and other site-specific requirements. 

In December 2019, the City issued the call for backyard cottage designs, receiving more than 160 submissions from Seattle’s design community. A panel of volunteers from the Seattle Design Commission, Seattle Planning Commission, Construction Codes Advisory Board, and the City’s design review boards identified 10 designs for permitting by the Seattle Department of Construction and Inspections (SDCI). The designs were selected based on estimated cost of construction, accessibility, green building principles, and compatibility with historical architecture.  

“Our technical staff have completed reviews on a range of cottage designs and sizes, which will reduce the time it takes to get started on construction,” said Nathan Torgelson, Director of the Seattle Department of Construction and Inspections. “Anyone thinking of adding a backyard cottage now has access to better information and an immediate head start on obtaining a permit.” 

In addition to helping homeowners determine whether an ADU could be in their future, ADUniverse also walks homeowners through the City’s requirements if they choose to rent out their new unit. The additional income may cover the cost of development, even though ADUs frequently rent for lower rates than similarly sized apartments. All rental homes in Seattle must be registered and inspected to ensure they meet quality and safety standards. With smaller and less expensive rental options scarce in single-family neighborhoods, backyard cottages and in-law apartments offer a more affordable housing option in areas where, at this time, apartment buildings and townhomes are not allowed. 

“Backyard cottages provide another family-sized option near schools and parks,” said Sam Assefa, Director of the Seattle Office of Planning and Community Development. “We have worked to lower the barriers to developing ADUs, another tool in our toolbox to support housing affordability.”   

Other features of the website include: 

  • Language accessibility: a feature that translates guidance and information into dozens of languages. 
  • A map of permitted ADUs and annual permitting data that charts the rapid growth in their numbers across the city. 
  • Dozens of cottage designs submitted during the City’s design competition. 

Seattle’s 2019 adopted changes allow for two ADUs on lots in single-family zones, increase the maximum size of a backyard cottage, eliminate parking requirements, lower lot size requirements, and other regulatory changes intended to encourage ADU construction. Since then, even as the city struggles with the impacts of the global pandemic, the number of ADUs permitted in 2020 has exceeded the pace of construction in 2019. This year, the City has approved 130 ADU permits though the end of June; in all of 2019, homeowners applied for 244 ADU permits. Seattle homeowners have built 2,800 ADUs since they were first allowed in 1994. 

ADUs have won praise from AARP and other advocates for older adults because they give homeowners flexibility to meet their changing needs and downsize, yet remain in their neighborhood. An additional home on-site is also a good option for multi-generational households, where grandparents can live close to their grandkids. 

“We applaud the City’s continuing commitment to expanding the production of accessory dwelling units citywide, including its launch of the ADUniverse website as a follow-up to its landmark reform of ADU rules in 2019,” said the Seattle chapter of the American Institute of Architects (AIA). “We appreciate the opportunity to partner with the City to help break down some of the regulatory barriers that slow down construction of new homes, and we share the city’s goal of encouraging more affordable homes throughout Seattle’s neighborhoods.”