Wash. Rev. Code § 46.96.210
The department shall determine and establish the amount of the filing fee required in RCW 46.96.040, 46.96.110, 46.96.150, and 46.96.200. The fees shall be set in accordance with RCW 43.24.086.
The department may also require the petitioning or protesting party to give security, in such sum as the department deems proper but not in any event to exceed one thousand dollars, for the payment of such costs as may be incurred in conducting the hearing as required under this chapter. The security may be given in the form of a bond or stipulation or other undertaking with one or more sureties.
At the conclusion of the hearing, the department shall assess, in equal shares, each of the parties to the hearing for the cost of conducting the hearing. Upon receipt of payment of the costs, the department shall refund and return to the petitioning party such excess funds, if any, initially posted by the party as security for the hearing costs. If the petitioning party provided security in the form of a bond or other undertaking with one or more sureties, the bond or other undertaking shall then be exonerated and the surety or sureties under it discharged.
RCW 46.96.210