The bill establishes new requirements for cities in Washington regarding the designation of historic landmarks. It mandates that cities must adopt or amend their development and zoning regulations to include specific criteria for designating properties as historic landmarks within one year of the bill's effective date. Notably, cities cannot designate a property as a historic landmark if it is less than 40 years old or if the designation would restrict the property's use, alteration, or demolition without the owner's written consent. Any designation made without this consent after the bill's effective date is rendered void until such consent is obtained. However, exceptions are made for properties within historic districts or those over 125 years old, provided proper documentation is submitted.

Additionally, the bill reenacts and amends existing law to clarify that certain actions taken by cities to implement these new requirements are not subject to administrative or judicial appeals. This includes actions consistent with the new sections added to chapters 35.21 and 35A.21 RCW, which outline the criteria for historic landmark designation. The bill aims to streamline the process for cities while ensuring property owners' rights are protected in the designation of historic landmarks.