This bill introduces new regulations regarding the placement of mobile dwelling units in residential zones within cities and counties in Washington State. It mandates that any city or county planning under RCW 36.70A.040 must allow at least one mobile dwelling unit on each residentially zoned lot, provided certain conditions are met, such as the presence of an existing housing unit and adequate utility services. The bill outlines specific requirements for utility connections, maintenance, and setback compliance for mobile dwelling units, which are defined as various types of vehicular units designed for travel or recreational use.

Additionally, the bill prohibits associations of apartment owners, condominium associations, homeowners' associations, and common interest community associations from creating any restrictions that would effectively prevent the placement of mobile dwelling units on residential lots, as stipulated in the new sections added to chapters 64.32, 64.34, 64.38, and 64.90 RCW. These provisions are set to expire on January 1, 2028. The legislation aims to enhance housing options by facilitating the use of mobile dwelling units in urban growth areas while ensuring compliance with safety and utility standards.