Internet Explorer 11 is not supported

For optimal browsing, we recommend Chrome, Firefox or Safari browsers.

Seattle Looks to Cottages for Affordable Housing

Cities are struggling to increase residential density without destroying single-family neighborhoods. That means the return of the backyard cottage.

It’s chilly, gray and raining.

In other words, it’s an utterly unremarkable spring day in Seattle, as the city’s urban planning supervisor Mike Podowski pulls up to a home in the Columbia City neighborhood southeast of downtown. The large clapboard-and-cedar house is a charming two-story Craftsman, but Podowski’s not interested. Instead, he makes a beeline for a freestanding structure in the backyard. “This is great!” he says, as the homeowner ushers him through a gate. “It’s an ideal set-up.”

Podowski has come to check in on one of Seattle’s fastest-growing new modes of housing: the backyard cottage. Since 2006, the city has allowed homeowners to build stand-alone cottages -- officially known as “detached accessory dwelling units” -- behind existing single-family homes. At first, the zoning change only applied to a few neighborhoods on the city’s south side, including Columbia City. But in November 2009, Seattle expanded the pilot program throughout the city, to any residential lot of at least 4,000 square feet. In the 18 months following the expansion, 57 backyard cottages have been permitted, and roughly 50 of those are either completed or nearly finished.

Like other mid-size cities that came of age in the first few decades of the 20th century, Seattle is made up largely of compact neighborhoods filled with single-family bungalows. Today, almost two-thirds of the city is zoned for single-family homes, so it’s harder for Seattle to accommodate its growing population -- the city swelled from 563,374 residents in 2000 to 608,660 last year -- without spreading farther and farther into the forests of the Pacific Northwest. That’s partly why the city saw backyard cottages as an attractive new alternative, a way to add affordable housing options without a wholesale redesign of the city’s signature neighborhoods.

These structures are small: Seattle’s code limits them to a footprint of 800 square feet, and they max out at 22 feet tall. Construction costs typically range from $50,000 to $80,000, although more elaborate units can cost upward of $140,000 to build. Some homeowners use the freestanding cottages as home offices, or as extra room for when relatives visit. Others are building them as in-law apartments for aging parents, or as crash pads for post-college children who can’t yet afford their own place. But a large number of homeowners are actually renting the cottages to tenants. (City law requires that the homeowners live on the property at least six months out of the year.) In some cases, the owners themselves have moved into the backyard cottage in order to rent out the larger house facing the street.

Seattle isn’t alone in its experiment with accessory dwelling units (ADUs). Localities everywhere from California to Minnesota to Massachusetts are re-examining their zoning laws and considering the role that ADUs can play in the makeup of their urban design. To be sure, there are plenty of critics who say backyard cottages are a bad idea, that renting out tiny apartments to strangers will destroy the character of a neighborhood. “We’re seeing both a continued resistance to [ADUs], but also a recognition that they provide a level of moderately priced housing,” says John McIlwain, a senior housing fellow at the Urban Land Institute. The “growing driver,” he says, are elderly parents who can’t afford nursing care, or who simply would rather age in place with their families. “That’s hard for a community to rally against,” he says. “And once you cross that threshold, it’s hard to exclude other uses for backyard cottages. We’re going to be seeing a lot more of this style of housing in the next several years.”

Backyard cottages are actually a throwback. Stand-alone in-law apartments, or “granny flats,” were common neighborhood features a century ago when multiple generations of a family lived together. By the 1950s, however, Americans were decamping for the suburbs, pursuing the dream of a single-family home on a large tract of land. Many urban zoning codes of the second half of the century essentially banned the construction of new backyard cottages.

But as attitudes toward urban density have shifted in recent years -- and as affordable housing has become scarce in many places -- more and more cities have reconsidered the granny flat as an important part of a neighborhood. Portland, Ore., and Santa Cruz, Calif., both have strong backyard cottage programs. Chicago and Madison, Wis., have considered relaxing their prohibitions against ADUs. Denver last summer revamped its entire city zoning code and now permits stand-alone ADUs in certain neighborhoods. California in 2003 passed landmark legislation essentially forcing localities to allow ADUs. (However, because cities were allowed to design restrictions as narrowly as they wanted, the law hasn’t had as much impact as it could have. Pasadena, for example, only allows ADUs on lots larger than 15,000 square feet, and mandates that an ADU have its own two-car garage. Only one backyard cottage has been built in Pasadena since the 2003 law took effect.)

Not everyone is pleased. Critics say the additional residents put a crunch on available street parking. Some neighbors worry about privacy with a two-story cottage looming just over the property line. But the biggest concern tends to be the notion that allowing backyard rental cottages will irrevocably change the feel of a neighborhood. While Seattle was debating the cottages in 2009, one real estate agent called the city’s proposal a “de facto rezone of the entire city,” adding, “There will no longer be single-family neighborhoods in Seattle.”

Podowski acknowledges that vocal objections from some critics made it “challenging to get the legislation passed. People are very protective of their single-family neighborhoods, and they weren’t sure this was something that was going to fit in.”

But after the city’s three-year experiment with ADUs in the southeast part of town, Podowski’s office conducted a survey of residents living near a permitted backyard cottage to gauge the impact the units had on neighborhoods. What the city found was something of a surprise. Eighty-four percent of the respondents said the ADUs hadn’t had any discernible impact on parking or traffic. What’s more, most people didn’t even know they lived near an ADU, says Podowski. “More than half of them didn’t even realize there was a unit next door. It really helped us to show that a lot of the fears people had about these were not going to be realized.”

That positive feedback helped encourage the city to expand ADU zoning citywide. Council members also eliminated a cap on the number of backyard cottages that could be built in the city, and they rejected a proposed “dispersion” requirement, which would have limited the number of ADUs in a given neighborhood. The city prepared a design guide for homeowners, tips on being a good landlord and ideas for how to best respect neighbors’ privacy. Since then, the 57 new permits for backyard cottages number “in the ballpark” of what the city had predicted, says Podowski, and they’re evenly spread in neighborhoods across Seattle.

To hear Podowski tell it, the benefits of an ADU are relatively prosaic: They’re good for aging parents, or the rental income can help offset a homeowner’s mortgage. But in some ways, backyard cottages represent a bigger shift than that. “Cities are struggling with, ‘How on earth do you increase density in a suburban neighborhood of single-family homes?’” says Witold Rybczynski, an urbanism professor at the University of Pennsylvania and the author of Makeshift Metropolis and other books on urban planning. “The backyard cottage is an easy first step toward densification,” he says. Unlike high-rise residential towers or even mid-rise apartment buildings, Rybczynski says, backyard cottages “are an effective way to increase density without a radical change in neighborhood standards.” With the twin challenges of accommodating an aging population and providing diverse housing options to an ever-growing pool of residents, an increasing number of cities may find a solution right in their own backyards.

Tina Trenkner is the Deputy Editor for She edits the Technology and Health newsletters.
From Our Partners