The proposed bill introduces the "Multifamily Housing Act" as a new chapter in Title 45 of the General Laws, aimed at encouraging the development of higher-density, mixed-use, and walkable urban communities. It establishes a base density requirement of at least two units per parcel for new construction in urban areas, specifically in municipalities with populations of 40,000 or more. The bill defines various types of middle housing, including duplexes, triplexes, quadplexes, cottage clusters, and townhouses, and permits their development in areas zoned for residential use that currently allow for the development of detached single-family dwellings.

Local governing bodies are allowed to regulate the site and design of these middle housing types, provided that such regulations do not, individually or cumulatively, discourage the development of all permitted middle housing types through unreasonable costs or delays. The bill specifies that it does not apply to municipalities with populations under 40,000, lands outside urban growth boundaries, or lands not zoned for residential use, including those primarily zoned for commercial, industrial, or agricultural use, as well as public uses or lands under interim zoning designations.

Additionally, local governing bodies may permit single-family dwellings in areas zoned for single-family use and other types of middle housing beyond what is mandated. The state building code standards committee is tasked with developing a model middle housing ordinance by December 31, 2025. Municipalities may designate zones that exempt properties within those zones from compliance with this section, with any exempted property subject to a 1% exclusionary zoning transactional fee, which will be remitted to Rhode Island housing to support affordable housing grant programs. The act will take effect upon passage.