RCW 18.106.130

All moneys received from certificates, permits, or other sources, shall be paid to the state treasurer as ex officio custodian thereof and by him or her placed in a special fund designated as the "plumbing certificate fund." He or she shall pay out upon vouchers duly and regularly issued therefor and approved by the director. The treasurer shall keep an accurate record of payments into said fund, and of all disbursement therefrom. Said fund shall be charged with its pro rata share of the cost of administering said fund.