Yet, there it was again, at the heart of a report released by the Seattle Planning Commission last week. A year and a half in the making, the report suggests officials pass legislation that would bring change to single-family zones: allowing large single-family homes to be subdivided into smaller units; placing size limits on new home construction to limit the spread of McMansions; and allowing development of duplexes, triplexes, small apartment buildings and other multi-family rental housing.

An independent body of volunteers appointed by the city council and mayor to suggest policy changes, the Planning Commission is making its pitch at a moment when other cities are finding success with similar approaches. Minneapolis recently made headlines for allowing triplexes in all residential neighborhoods and apartment buildings near transit hubs. Olympia passed its own plan this fall to encourage construction of multi-family housing. Portland is likely to pass a “residential infill” plan next year.

There is another example of the planning commission's suggestions somewhere else: Seattle's past.

The recommendation to allow duplexes, triplexes and small apartments — the so-called “missing middle” between detached single-family housing and big apartment buildings — is not actually a new idea. In a sense, they are calling on the city to re-legalize housing that was once not so missing. New construction of those housing types is still allowed in about 12 percent of the city’s residential areas. But in the residential core of many neighborhoods — including Wallingford, Queen Anne, and Greenlake — you are either building single-family homes or nothing. Still, if you take a stroll through any of these neighborhoods, you’re sure to find a few duplexes, triplexes, and even small apartment buildings mixed in among the stand-alone houses, byproducts of an earlier era of Seattle zoning.

At the turn of the 20th century, Seattle didn’t have a zoning code. Instead, it had a building code. Though the distinction seems minor, the building code only regulated size, not use. So as long as a building didn’t exceed a neighborhood’s size limits, it could be subdivided into as many units as the builder deemed practical. “There was a huge amount of flexibility in what could be built,” explained Margaret Morales, a researcher at the urbanist think tank Sightline, who has studied Seattle’s zoning history. “You could build a duplex or triplex almost anywhere in the city except downtown.”

In the early 1900s, Seattle neighborhoods were developing around the streetcar system, which at the time branched out from downtown to inner neighborhoods such as Woodland Park and Madison Valley. Duplexes, triplexes and apartments built over corner stores were logical choices, not only because people wanted to live near transit, but because the population was exploding, from 80,671 people in 1900 to over 315,000 in 1920.

“We had really naturally occurring, robust transit-oriented development,” said University of Washington College of the Built Environments associate professor Rick Mohler, who sits on the Seattle Planning Commission. “Seattle had density occurring along streetcar lines and near them for a few blocks. It made sense in the pre-automobile era to have housing near streetcars.”

Seattle’s first zoning ordinance was implemented in 1923. It dictated not just building size, but how land within a neighborhood was allowed to be used. Its function was, in part, to create space between where people lived and commercial and industrial operations. But, said Mohler, “Part of it was in the interest of exclusion, frankly. There was concern about people of color and to some extent renters moving into the neighborhood.”

By the time Seattle created its first zoning plan, the U.S. Supreme Court had already ruled that explicitly-segregationist zoning was unconstitutional. But city planners recognized that dictating the types of housing allowed in certain areas could serve as a stand-in for explicitly racial zoning, especially in tandem with property deeds that banned the sale of housing to non-white buyers.

A section of Seattle's 1923 zoning plan, which created the city's single-family neighborhoods. (Courtesy of the City Clerk's Office)

St. Louis city planner Harland Bartholomew was a pioneer of American zoning. According to historian Richard Rothstein, Bartholomew stated his goal for the 1919 St. Louis zoning plan was to “‘preserve the more desirable residential neighborhoods,’ and to prevent movement into ‘finer residential districts … by colored people.’” The St. Louis plan became a model for other cities who began hiring Bartholomew as a consultant, including Seattle for its 1923 plan.

Seattle’s zoning plan created six types of districts: first and second residential, business, commercial, manufacturing and industrial. First residential districts allowed single-family homes as well as churches, parks, libraries, schools and rail stations, but banned the multi-family dwellings that had been largely unrestricted in the building code days. These structures were restricted to second residential districts, which covered about 35 percent of the city.

“Single-family zoning was a strategy of exclusion,” said Mohler. “If you make the properties expensive enough, you automatically exclude some people.” With people of color experiencing poverty at disproportionate rates to White people, making certain neighborhoods more expensive by limiting them to standalone homes ensured that Seattle remain segregated.

Seattle, as with most cities in the first half of the 20th century, further ensured segregation through the use of redlining and racially restrictive neighborhood covenants.

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