The bill aims to enhance housing options in Washington by allowing existing residential lots to be split into new residential lots through a streamlined administrative process. This initiative is designed to support homeowners facing changing life circumstances and to provide prospective homebuyers, particularly first-time buyers, with more affordable housing opportunities. The legislation mandates that cities complying with minimum density requirements must establish a process for simultaneous review and approval of administrative lot splits and residential building permits, facilitating the development of middle housing or single-family homes.

Key provisions include that the lot split process may only require an administrative decision without a public hearing, provided certain conditions are met, such as compliance with development standards and the absence of displacement of renters. The bill also stipulates that cities cannot impose limits on the number of dwelling units below what is allowed by existing zoning laws and that any newly created lots must adhere to local density requirements. Additionally, cities are granted immunity from liability related to the approval of lot splits, and the Department of Commerce is tasked with developing guidance and providing grants to assist cities in implementing these requirements.