This vote is a big deal.
In the midst of a construction boom, how should the city make sure some of all the new apartments going up are affordable? STEVE ESTVANIK/SHUTTERSTOCK

Do you ever look around at all these new buildings and expensive rents and think, "The city should really make these developers build some affordable apartments?" Good news: They're working on it.

In a quick vote during a hectic meeting yesterday, the Seattle City Council passed a law known as Mandatory Housing Affordability or MHA or sometimes "mandatory inclusionary zoning." The law will require developers in some neighborhoods to include affordable units in new apartment buildings or pay a fee toward affordable housing instead.

The policy came out of last year's housing affordability committee, known as HALA, and is part of the so-called Grand Bargain, an agreement between city officials and developers in which some developers promised not to sue the city over the legislation. Mayor Ed Murray says the program will create 6,000 affordable units in the next decade, part of his larger goal to build 20,000 new income-restricted housing units in the next 10 years.

But there are limits to how beneficial this program will be.

"Affordable" here is defined as housing for people making 60 percent of the area median income—about 54,180 for a family of four—or less. Put another way: about $1,000 a month for a one-bedroom. (Yes, this definition of "affordable" leaves a lot of people out. The city is attempting to address housing for people of even lower incomes through a different program: the $290 million housing levy, which passed earlier this month and will fund subsidized housing.)

Some fear that allowing developers to pay a fee toward affordable housing instead of building affordable units themselves will worsen economic segregation by concentrating affordable housing where land is cheapest.

And, while the law's passage is a big symbolic victory for the mayor's housing plans, it won't take effect for a while. Later this year and throughout the first half of 2017, the city council will consider upzones (allowing taller buildings) in the University District, South Lake Union, Downtown, and the Central District. Only once any of those upzones pass will the affordability requirements take effect in that neighborhood. (Why? City officials say they're required to offer developers a benefit before they can take something from developers. The benefit is the extra height; the taking is the affordable units/fees.)

Important specifics of the program—like just how much developers will have to provide or pay—also remain unspecified. The city has estimated that it will require between 2 and 7 percent of the apartments in a building to be set aside affordable or an in-lieu fee of between $5-14 per square foot, depending on where the buildings are, but those numbers are still just estimates. Thanks to an amendment from Council Member Lisa Herbold, displacement risk will also be taken into account in deciding the rules.

Even as the "grand bargain" signaled a truce between the city and developers, local developer lobbyist Roger Valdez has railed against the MHA policy, claiming it will drive up housing costs. Anti-growthers like John Fox also oppose the policy because of fears about displacement.

Once the upzones take effect and the math is nailed down, any apartments created through the program would have to stay affordable for 75 years. Council Member Rob Johnson, who chairs the council's land use committee, called the law "one of the most ambitious efforts Seattle has ever undertaken to address our growing need for affordable housing in our city."