Washington Revised Code Title 49. Labor Regulations § 49.46.160. Automatic service charges

(a) “Employee” means nonmanagerial, nonsupervisory workers, including but not limited to servers, busers, banquet attendant, banquet captains, bartenders, barbacks, and porters.

(b) “Employer” means employers as defined in RCW 49.46.010 that provide food, beverages, entertainment, or porterage, including but not limited to restaurants, catering houses, convention centers, and overnight accommodations.

(c) “Service charge” means a separately designated amount collected by employers from customers that is for services provided by employees, or is described in such a way that customers might reasonably believe that the amounts are for such services. Service charges include but are not limited to charges designated on receipts as a “service charge,” “gratuity,” “delivery charge,” or “porterage charge.” Service charges are in addition to hourly wages paid or payable to the employee or employees serving the customer.