Illustrations: City of Seattle
Hello there, and welcome to this info page about all things related to backyard cottages and in-law apartments in Seattle. We put this guide together for you, the Seattle homeowner interested in learning more about building a cottage in your backyard or an apartment in your basement. Perhaps you want some rental income or just have some extra space. If so, a backyard cottage or ADU can be a great choice, but the regulations can be a bit confusing, and Seattle is in the midst of changing them. There's probably more information here than you can take in, but we hope you can use it to get ideas and get started on your backyard cottage project. If there's anything you think should be included in this guide, we'd love to hear about it. You can email email@example.com. Be sure to check back frequently or sign up for updates because we'll be adding new information as it becomes available.
Sometimes called “mother-in-law apartments,” accessory dwelling units, or ADUs, these are self-contained living spaces built into your home. To create these apartments, you can convert your basement by adding an outside entrance, egress windows, and a small kitchen, or you can add on to the back or side of your home. To be official, an ADU must have its own private entrance and meet certain other requirements.
Detached accessory dwelling units, or DADUs, are small, standalone houses built behind your main home. They allow you to maintain your privacy and all the square footage in your main house while creating extra living space. DADUs are also known as "backyard cottages." Homeowners often opt to build these over a garage.
There are many benefits to building these units alongside an existing single-family home or townhome.
So you want to build a backyard cottage or ADU? Great! The first step is to make sure you know all the rules. There are some major changes to the regulations in the works, but let's take a look at the current regs.
Attached ADUs (in-law apartments) have been allowed in all single-family homes in Seattle since 1994. As of 2016, there are just over 1,000 units. Here is a rundown of the current ADU regulations:
Backyard cottage regulations are more hotly contested and a bit more complicated than those for in-law apartments. The city started a pilot program in 2006, allowing DADUs to be built in Southeast Seattle. It was considered a success, and the city expanded the program to include all of Seattle in 2009. However, as of 2016, only 221 backyard cottages have been built out of the roughly 75,000 single-family lots that are eligible.
If you're thinking about investing in a backyard cottage, you may want to check with a knowledgeable builder or architect about your eligibility or refer directly to Seattle Municipal Code 23.44.016.D.8. Here is a summary of the current regulations:
Seattle City Council
Back in May of 2016, Councilmember Mike O'Brien proposed new regulations that would make it easier to build backyard cottages and in-law units in Seattle. Here is a rundown of the proposed changes:
Seattle City Council
The Office of Planning and Community Development issued a State Environmental Policy Act (SEPA) Determination of Non-Significance (DNS) in May of 2016 on my proposal. Following the release, the Queen Anne Community Council appealed the DNS to the hearing examiner. This past December we received the response from the Hearing Examiner that reversed the DNS. After thorough examination of the Hearing Examiner’s response, we have decided to pursue a full environmental impact statement (EIS). This process will likely take a year to complete. The full EIS will enable us to look deeply into the potential environmental impacts of the proposed code changes and inform our proposal before we bring it to the Planning, Land Use and Zoning Committee.
There will be multiple opportunities for input during the EIS process. We will keep you informed of these opportunities for public comment and encourage you to engage. When the EIS is complete, we hope to bring legislation to committee by mid-2018.
I believe lowering the barriers to creating backyard cottages and in-law apartments is an important part of addressing affordability across the city, and am looking forward to continuing to pursue this legislation.
If you have further questions, please reach out to Susie Levy – firstname.lastname@example.org or call our office at 206-684-8800.
Stay up to date on the latest in-law apartment and backyard cottage news. Want to explore CRD's full-service design-build approach to backyard cottages and ADUs, please contact us.