Mar 13, 2023 - News

Lawmakers advance plan to legalize more duplexes and quadplexes

Illustration of the Washington State Capitol with lines radiating from it.

Illustration: Brendan Lynch/Axios

Washington's state House passed a measure last week that would require cities — including Seattle — to allow denser housing on most lots currently zoned for single-family homes.

Why it matters: Republicans and Democrats alike are calling for solutions to address the state's housing crisis, which is causing rents and home prices to rise faster than incomes.

By the numbers: The state Department of Commerce estimates that Washington state needs to add more than 1 million housing units over the next 20 years to keep up with population growth.

What's happening: The measure passed on a bipartisan 75-21 vote and would require Seattle and its suburbs — plus other cities with at least 75,000 residents — to legalize quadplex housing on at least three-fourths of their residential lots.

  • In most areas near major transit stops, these cities would have to allow the construction of buildings with at least six units per lot, also known as sixplexes.
  • This kind of denser development is often called "missing middle" housing, because it offers an option between large multifamily apartment buildings and single-family homes.

State of play: Right now, most residential areas in Seattle are not zoned to allow quadplexes and sixplexes. They allow mainly single-family homes, although backyard cottages and mother-in-law apartments can be added in most cases.

The quadplex to sixplex requirements would also apply to most suburbs of the state's largest cities, regardless of those suburbs' population numbers.

  • Other cities between 25,000 and 75,000 residents would have to allow at least duplexes on most residential lots, and four or more units on most lots close to transit.

What they're saying: State Rep. Jessica Bateman (D-Olympia), the bill's sponsor, said the lack of available units is causing housing prices to skyrocket, putting homeownership out of reach for too many people.

Context: Last year, Seattle Mayor Bruce Harrell expressed concern that a similar upzoning proposal didn't do enough to prevent gentrification and displacement.

  • In a statement to Axios last week, Harrell spokesperson Jamie Housen said the mayor remains focused on the need to "ensure that seniors, communities of color, and people with disabilities have the choice to stay in their homes."
  • In a nod to those concerns, this year's bill has been amended from an earlier version. It now would let cities exclude some areas at risk of displacement from the higher density requirements.

What's next: The measure still must pass the state Senate and not be vetoed by the governor to become law. The Legislature is in session through late April.


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