Wash. Rev. Code § 35.99.050
A city or town shall not place or extend a moratorium on the acceptance and processing of applications, permitting, construction, maintenance, repair, replacement, extension, operation, or use of any facilities for personal wireless services, except as consistent with the guidelines for facilities siting implementation, as agreed to on August 5, 1998, by the federal communications commission's local and state government advisory committee, the cellular telecommunications industry association, the personal communications industry association, and the American mobile telecommunications association. Any city or town implementing such a moratorium shall, at the request of a service provider impacted by the moratorium, participate with the service provider in the informal dispute resolution process included with the guidelines for facilities siting implementation.
RCW 35.99.050