As our region continues to debate how to add much-needed housing in urban areas and address our ongoing housing affordability crisis, much attention has been given to accessory dwelling units (ADUs) and detached accessory dwelling units (DADUs).
Sometimes referred to as mother-in-law apartments, ADUs are small homes that occupy the same lot and are within single-family homes. Stand-alone ADUs, or DADUs, are commonly referred to as backyard cottages.
ADUs and DADUs offer significant benefits and should be encouraged throughout our region. They provide a fundamental housing choice for retirees who want to age in place and for young adults looking for their first home, as well as college students, extended family and others. They also give homeowners a way to earn rental income. Furthermore, by offering an affordable housing choice in cities, ADUs and DADUs are critical tools for accommodating growth in the very places where it makes sense—near job centers and existing infrastructure.
ADUs are also considered an environmentally-friendly housing option, given their small size and the fact that residents tend to drive less, resulting in lower carbon emissions.
And yet, despite their promise, not everyone is embracing this housing choice. Some jurisdictions have been slow to adopt code changes to allow ADUs and DADUs. Even when ADUs are allowed, people who want to build them often face burdensome restrictions and regulations. Examples range from off-street parking and owner-occupancy requirements to expensive development charges and fees.
Concerns about adding more density in existing single-family neighborhoods, potential impacts on traffic and parking, and the catch-all argument around changing the character of existing neighborhoods have all been cited as reasons for limiting this small housing type.
While neighborhood angst over new development is nothing new, it is important to understand the costs of inaction. A failure to add more housing in existing urban neighborhoods means more families and workers are pushed farther away from job centers and communities they would like to call home. These same individuals are then forced into long commutes, adding environmental costs while negatively impacting their quality of life and community connection.
Curtailing innovative housing types like ADUs and DADUs further limits the supply of homes and the range of housing choices in our urban areas. This only drives up the cost of existing housing and adds unnecessary barriers for new and longtime residents alike, as they seek to either move here for a job or simply attempt to remain in neighborhoods in which they have long resided.
While much is being done to add density to areas zoned for multifamily housing and to drive growth to urban villages and town centers, single-family neighborhoods have a role to play, too. And though not a panacea for our housing crisis, ADUs are promising tools for increasing housing stock in the very places where many families want to live.
The city of Seattle estimates, for example, a proposal to ease ADU rules now working its way through the environmental review process would create more than 3,000 housing units over ten years. The proposed ADU rule changes introduced at the Seattle City Council would make an estimated 70,000 lots eligible for ADUs in Seattle. The city is currently analyzing alternatives as part of a State Environmental Policy Act (SEPA) review, with a final report due soon.
Some notable examples of other cities that have successfully encouraged more production of ADUs by passing reduced zoning requirements include Portland, Oregon and Vancouver, B.C.
While ADUs represent just one of many tools needed to address our housing affordability crisis, they are an important part of the solution. Cities in our region need to step up and do more to encourage this housing type by adopting flexible ADU rules. Doing so can benefit our communities by adding a much-needed and affordable housing choice.
Jeff Pelletier AIA, CPHC®, is Principal at Board & Vellum and a member of the Master Builders Association of King and Snohomish Counties.