The Urbanist reported that Seattle’s interim middle housing ordinance has produced 588 new homes on 147 lots in just over one year, with four freestanding houses on a single lot emerging as the predominant project type. Construction permits filed since the ordinance took effect in July 2025 show 65 projects adding four freestanding homes, 52 adding a pair of duplexes, and 30 adding a duplex plus two freestanding homes. Seattle typically delivers around 10,000 new homes in an average year, so fourplexes remain a small slice of overall production.
Fourplexes Fill Lots That Held Single Homes
The law, state House Bill 1110 passed in 2023, required major cities like Seattle to allow middle housing by July 2025. Seattle met the deadline through an interim ordinance after the Harrell administration struggled to complete its Comprehensive Plan on schedule. The result is that lots which previously would have held one home now hold four, six, or more units. Architect Matt Hutchins told The Urbanist that stacked flats remain rare, estimating that “maybe 5% of the townhouse projects become stacked flat projects,” with townhomes serving as the workhorse product.
Tree Canopy Loss Predates the Middle Housing Law
Single-family zones lost 87 acres of net tree canopy from 2016 to 2021, according to the city’s official tree assessment, while multifamily and mixed-use zones lost just 24 acres over the same period despite adding more than 40,000 new homes. Park and natural lands accounted for 111 acres of net canopy loss. The middle housing changes did not create the teardown trend; they altered what gets built on cleared lots, shifting from larger single-family homes to fourplexes.
Columnist Alex Fryer Owns a Million-Dollar Home
Seattle Times columnist Alex Fryer owns a 2,400-square-foot home in the Admiral District valued at more than $1.1 million per RedFin. King County property records show he and his spouse bought the 1946-built house in 2005 for $438,000. Fryer has argued that the new housing produces “architectural gigantism” and that existing homes should be subdivided instead, a concept Hutchins called “wishfully naive” because converting houses into triplexes is legal today but not economically viable.
Questions Readers Ask About Seattle’s Middle Housing
The 2023 state law set a minimum standard that major cities like Seattle had to adopt by July 2025, allowing duplexes, triplexes, fourplexes, and sixplexes in areas previously zoned for single-family homes.
Single-family zones lost 87 acres of net canopy from 2016 to 2021, while multifamily and mixed-use zones lost only 24 acres despite adding more than 40,000 homes, according to the Seattle Office of Sustainability and Environment.
Seven Seattle City Council positions will be on the ballot in fall 2026, with middle housing expected to feature in the campaigns.
Worth a look