For purposes of all rules of the commission, Eastern and Western Washington are defined as:
Eastern Washington - All lands lying east of the Cascade Crest Trail and east of the Big White Salmon River in Klickitat County.
Western Washington - All lands lying west of the Cascade Crest Trail and west of and including the Big White Salmon River in Klickitat County.
Wash. Admin. Code § 220-200-020
Statutory Authority: RCW 77.12.040. 86-09-024 (Order 271), § 232-12-809, filed 4/10/86; 82-11-099 (Order 184), § 232-12-809, filed 5/19/82.