Wash. Rev. Code § 49.70.177
If payment of any fee assessed under RCW 49.70.170 is not received by the department by the due date, there shall be assessed a penalty of five percent of the amount of the fee. If the fee is not received within thirty days after the due date, there shall be assessed a total penalty of ten percent of the amount of the fee. If the fee is not received within sixty days after the due date, there shall be assessed a total penalty of twenty percent of the amount of the fee. No penalty added may be less than ten dollars. If a warrant is issued by the department for the collection of fees, penalties, and interest, there shall be an additional penalty of five percent of the amount of the fee, but not less than five dollars nor more than one hundred dollars. Warrants shall earn interest at the rate of one percent per month, or fraction thereof, from and after the date of entry of the warrant. The department may utilize the procedures for collection of fees, penalties, and interest set forth in Title 51 RCW.
RCW 49.70.177