With interim development regulations regarding new housing types on Mercer Island set to go into effect on June 30, the city has already been receiving inquiries from builders, developers and property owners about what can occur in that realm.

Alison Van Gorp, the city’s deputy director of Community Planning & Development, said MI held its initial pre-applications meeting for a middle housing project on June 24.

“I think it remains to be seen whether people apply for permits and what those look like, but there’s definitely some early interest and inquiries coming in,” she said about the early progress.

In complying with the 2023 state requirements of cities increasing housing options and creating less-expensive housing, Mercer Island City Council adopted a series of interim regulations in February and March of this year, according to the city.

The state legislature passed a host of housing bills in 2023 with state-mandated deadlines set for June 30. After engaging in further public outreach and analysis, Mercer Island plans to adopt permanent regulations starting in 2026, the city said.

Additional public outreach could be holding some open houses with residents and obtaining their thoughts on housing types, building design and more, Van Gorp said.

Van Gorp explained that the passage of the new housing bills includes city requirements to allow new housing types, middle housing and accessory dwelling units (ADUs).

Prior to June 30, Mercer Island allowed one 900-square-foot ADU per residentially-zoned lot; from June 30 and beyond, the city will be allowing two ADUs per residentially-zoned lot that each extend up to 1,000 square feet, according to Van Gorp and city documents.

“In addition, all these new middle housing types will be permitted and that will include duplex, triplex, fourplex, stacked flats, courtyard apartments and townhomes. We’re required to allow six out of nine housing types the state had identified and those were the six that we chose to allow at this point,” Van Gorp said.

According to the city, “The interim development regulations also permit a new type of land division, Unit Lot Subdivision, that enables the individual sale of these housing units, separate from any primary unit located on the property.”

Mercer Island has allowed ADUs since the 1990s and Van Gorp said there are around 200-300 in existence on the Island.

“I think that’s been a pretty successful housing type for Mercer Island as far as providing flexibility to have parents or kids living on a property. Or some people use it for a nanny or a caregiver,” she said, adding that ADUs could be rental units, as well.

For more information, visit: https://letstalk.mercergov.org/middle-housing-adus