Authorizing middle housing in unincorporated growth areas and unincorporated urban growth areas, certain limited areas of more intensive rural development, and fully contained communities.

HB 1840 authorizes counties to allow "middle housing" (like duplexes, triplexes, or townhouses) in designated unincorporated urban growth areas, specific rural development zones, and established communities. It requires at least one middle housing unit per single-family lot in urban areas and limits these developments to four units per lot in rural zones. The bill mandates that counties apply the same zoning, permit, and environmental rules to middle housing as to single-family homes, while requiring sewer service for rural middle housing. This policy aims to increase housing density without new infrastructure, directly affecting homeowners and developers in targeted areas.