Missing Middle Housing Types Case Studies

Issues Addressed:
Affordable Housing Housing Costs Housing Options Multigenerational Sustainable Housing

Dover, NH

Dover's zoning ordinance has long been a model for aligning zoning rules with housing production needs and traditional neighborhood design. All of its residential districts allow—whether by-right or by Special Exception—homes with up to four housing units per structure. (In lower-density areas, these housing types are only allowed in cluster housing developments.) Lot size and setback requirements provide reasonable opportunities to produce housing, with minimum lot sizes for missing middle housing types tending to be less than an acre. Dover Zoning Code, ​​https://www.dover.nh.gov/Assets/government/city-operations/2document/planning/Regulations/Zoning%202018.pdf
An excerpt from the Dover zoning code.

Hanover, NH

In 2022, Hanvoer town meeting approved a new base zoning district along one street in Downtown Hanover near Dartmouth College. The stated goal of the zoning amendment is "to increase the number of residential units," according to the zoning text itself. The existing neighborhood fabric has a mix of housing types, including missing middle housing types. Under the new rules, single-family, twofamily, and multifamily hosuing is allowed by-right. Importantly, the district's dimensional rules and dimensional rules were also relaxed to enable more infill small multifamily. Main Wheelock's new zoning was accompanied by design guidelines that specify architectural treatment of new housing. The zoning change was at least ten years in the making, with one failed proposal in 2015. In the 2022 effort, Dartmouth students were significantly involved in advancing the proposal and in the Town Meeting vote itself. At least area landowner had plans to add new housing to the area upon the amendment's passage.

Grand Rapids, MI

In 2008, Michigan’s second largest city updated their zoning to allow duplexes in previously single-family-only zones. (The amendments also allowed mixed-use development in commercial districts, and included “form-based light” provisions.) Duplexes were allowed by Special Permit on corner lots under the 2008 law. In 2018, An excerpt from the Dover zoning code. 72 Missing Middle Housing Types the City amended the new code to remove the Special Permit requirement and allow duplexes by-right.
A prewar duplex in Grand Rapids—the type of housing the city hoped to allow again.

Bend, OR

In 2019, Oregon passed a law to allow some missing middle housing types in all single-family zones across the State, giving discretion in implementation to a state land use board. In additional to allowing duplexes, fourplexes, and other small multifamily options, the board reduced local parking minimums for small multifamily homes in large Portland-area cities. Bend, Oregon became the first community to comply with the law locally, adjusting its zoning to allow duplexes and fourplexes. Those changes, combined with a strong real estate market, with 650 units under construction in early 2022.