An intercounty utility company is defined in Washington statute as an electric, gas, telephone, wireless telephone, railroad, or airline company that operates across either a county or Washington State border. The laws defining these companies can be found under Revised Code of Washington (RCW) 84.12.200 and Washington Administrative Code (WAC) 458-50-020. Intercounty or interstate companies have physical assets located and operate in more than one county or more than one state. Private railcars are also considered to be intercounty or interstate utility companies, but are defined under a different statute (RCW 84.16.010).
Any company meeting these definitions must file an annual report with the Department of Revenue for property assessment.