This bill amends Chapter 65, Title 67 of the Idaho Code by adding a new section, 67-6541, which establishes provisions regarding twin homes and duplexes. It prohibits cities from enacting or enforcing ordinances that ban these types of housing in residential zoning districts where single-family dwellings are allowed. The bill defines a "twin home" as a residential building with two separate living units that share a wall, with each unit independently owned. By February 1, 2027, cities must amend their comprehensive plans and land use regulations to permit twin homes and duplexes on lots where single-family dwellings are permitted, while also prohibiting certain restrictions such as minimum lot size requirements and excessive fees.

Additionally, the bill mandates that twin home or duplex projects meeting established land use requirements be approved administratively, similar to single-family dwellings, unless there are infrastructure constraints. It also stipulates that any local government approval standards must be clear and objective, ensuring they do not discourage the development of twin homes or duplexes. The provisions apply only to cities with populations over 10,000 and do not supersede existing laws that protect public health, safety, and welfare. The bill includes a severability clause and declares an emergency, making it effective on July 1, 2026.