The ongoing debate over whether to allow more mother-in-law apartments and granny flats (attached and detached accessory dwelling units) in Seattle’s single-family zones is the best example of Seattle’s interminable conversation about density: Some homeowners believe single-family zoning is a sacred tenet of city code and shouldn’t be tinkered with, while Seattle city planners believe, correctly I think, that adding more housing options like the attached and detached accessory dwelling units (ADUs and DADUs) is an important strategy for building a sustainable city.
I wrote a lot about this specific fight last year on PubliCola. When the city’s Office of Planning & Community Development ruled that the city didn’t need to do any further study before moving forward with its plan to allow more ADUs and DADUs in single-family zones, a group of homeowners appealed the ruling; I covered Day 1 and Day 2 of the city hearing.
A few months later, I wrote about the City Hearing Examiner’s final decision on the appeal—she decided in favor of the homeowners, saying the city needed to do a more comprehensive study on the impacts of allowing more ADUs and DADUs.
I also wrote an overview of the case for Seattle Met magazine.
This week, Sightline researcher and Seattle super urbanist Dan Bertolet published a detailed report on the issue.
He seconded my belief that the Hearing Examiner’s call for further study actually comes with a silver lining. But more important, he shot down the Hearing Examiner’s ruling point by point.
On fears of land speculation & displacement.
The hearing examiner’s conclusion that the proposed ADU changes would increase displacement… relies on one witness’ opinion that the proposed liberalization would push the teardown economics across a tipping point, an opinion that cannot supported by on-the-ground data because there is none. No such sordid tales of ADU speculators run amok have yet to emerge from Vancouver, though home values are even higher there than in Seattle.
…. The hearing examiner got it backwards: building more ADUs is not a cause of displacement; it’s a cure. As I detailed in a previous article, economic displacement (caused by rising rents) is displacing far more, probably at least ten times more, people in Seattle than is physical displacement (caused by demolition of existing low-cost housing). In the (likely rare) cases when an existing home is replaced by a new house with an ADU, the net effect citywide is less displacement, because creating more homes addresses the primary cause of rising rents: not enough homes for all the people who want to live in Seattle.
…The city can address the displacement issue directly to head off future attacks through SEPA against proposals to spur in-city homebuilding. Addressing it directly means establishing the fact that when there’s a shortage of housing across a city, adding new homes reduces net displacement, full stop. Even if the new homes are more expensive than the old ones. Because it all comes down to basic math: the bigger the gap between the number of homes and the number of people who want them, the more the competition for scarce housing floods down the market and pushes people with lower incomes out of the city.
It follows that every time a speculative developer replaces an existing house with a new one that includes an ADU (or two), it’s a net win for housing equity. Conversely, every time a teardown is replaced with the largest, most expensive house that will fit on the lot but that can only accommodate one family, it’s the worst possible outcome for equitable access to housing. If city officials fail to unequivocally demonstrate these fundamental truths, they will lose the argument from the start.
On the supposed necessity of the “owner occupancy requirement”
Some cities have rationalized owner occupancy requirements as a means to “preserve neighborhood character,” based on the perception that rental units may not be well maintained. But if this argument were valid, it would also justify applying the same rule not just to ADUs but to all rental homes, including everything from single-family houses to duplexes, rowhouses, and large apartment buildings. Singling out ADUs is discriminating against renters in the most sought-after residential neighborhoods. In a similar vein, some Seattle officials hope to assuage fears that speculative developers would build “backyard cottages that don’t fit the character of the neighborhood.” Such arguments prioritize some people’s aesthetic tastes over other people’s need for housing.
On anxiety about parking
Regarding parking, yes, removing the off-street requirement for ADUs might increase competition for street parking. A 2014 study in Portland found that on average, each ADU generates 0.46 cars parked on the street. But requiring off-street parking has numerous and hefty adverse impacts. Overall, off-street parking quotas make housing more expensive and deepen car dependence—in direct contradiction to two of Seattle’s most urgent aspirations for the future.
Besides, the City of Seattle has no obligation to provide convenient parking, free of charge, on publicly owned streets, to single-family homeowners—the vast majority of whom already have plenty of car-storage space on their own property. In an age of impending climate crisis, in a city where close to half of greenhouse gas pollution comes from cars, it’s ludicrous that a policy change as benign as allowing more ADUs can be contested through the State Environmental Policy Act over parking.
On worries about overburdening infrastructure
The SEPA appeal ruling also cited lack of analysis of public infrastructure, but most of these concerns are based on an outdated context. First of all, as an article I will publish soon details, in most of Seattle’s single-family areas, population density has decreased over the past few decades with the decline in average household size. In other words, in the not too distant past, existing infrastructure adequately served more people in most neighborhoods where ADUs would be built. The ruling calls out stormwater management in particular, but today’s stringent regulations ensure that any new construction will not increase polluted runoff, and in fact, will likely reduce it.
Furthermore, urban infill projects like ADUs typically cost less to serve with infrastructure compared with the alternative scenario of new homes forced out to more sprawling, suburban locations. Here again, the appeal ruling ignores modern reality—in this case, that urban infill housing lowers per-capita public expenditures on infrastructure.
Bertolet didn’t simply make a convincing argument against the Hearing Examiner’s ruling, he also made an eloquent argument for mother-in-law apartments and backyard cottages:
Tucked away on single-family lots, ADUs expand access to great neighborhoods for families who can’t afford a pricey, larger detached house. At the same time, they let more people live near jobs and services, shortening carbon pollution-spewing commutes and reining in sprawl.
Building more ADUs in Seattle’s neighborhoods will:
- modestly reduce car trips across the metro area;
- decrease car dependence and increase transit ridership, walking, and cycling;
- slow sprawl and thereby protect forest and farmland from development on the metropolitan periphery;
- improve integration by class (and therefore likely by race) in neighborhoods that currently exclude middle- and working-class people;
- allow less affluent families to live near the city’s best parks, schools, and job opportunities;
- trim consumption of fossil fuels; and
- reduce pollution of water and air—and therefore climate change.
These benefits of compact communities—of density—are ubiquitous in the past three decades’ research on cities. Indeed, the main lesson of that entire body of work is that compact, transit-rich, walkable, mixed-use, mixed-income cities are critical ingredients to a sustainable future. Seattle officials shouldn’t have to prove this anymore than they have to prove that hydro- and wind-powered Seattle City Light electricity is better for the planet than the coal power that many rust belt cities rely on.