This bill introduces new regulations regarding the placement of mobile dwellings on residential lots in urban growth areas within Washington State. Specifically, it mandates that cities and counties planning under RCW 36.70A.040 must allow up to two mobile dwellings on each residentially zoned lot, provided certain conditions are met, such as the presence of an existing housing unit and compliance with utility connection requirements. The bill also defines "mobile dwelling" to include various types of recreational vehicles and tiny houses on wheels. Additionally, it requires cities to incorporate these regulations into their comprehensive plans and development regulations by specified deadlines.

Furthermore, 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 dwellings as outlined in the new regulations. These provisions are set to expire on January 1, 2028. The bill also includes a clause stating that if specific funding for its implementation is not provided by June 30, 2025, the act will become null and void.