Wash. Rev. Code § 41.04.030
Upon being authorized by any employee or group of employees so to do under the provisions of RCW 41.04.020, the auditor or other person authorized to draw warrants against the funds involved is authorized, and if such medical, surgical, and hospital care or either of them, or life insurance or accident and health disability insurance is to be provided on a group basis for groups each of not less than twenty-five individuals such auditor or other person is hereby required, to draw and issue a proper warrant or warrants directly to and in favor of the person, firm, or corporation, or organization named in the authorization for the total amount authorized to be deducted from the payroll of any such office, department, division, or institution.
RCW 41.04.030