Wash. Rev. Code § 36.34.150
Any person desiring to lease county lands shall make application in writing to the board of county commissioners. Each application shall be accompanied by a deposit of not less than ten dollars or such other sum as the county commissioners may require, not to exceed twenty-five dollars. The deposit shall be in the form of a certified check or certificate of deposit on some bank in the county, or may be paid in cash. In case the lands applied for are leased at the time they are offered, the deposit shall be returned to the applicant, but if the party making application fails or refuses to comply with the terms of his or her application and to execute the lease, the deposit shall be forfeited to the county, and the board of county commissioners shall pay the deposit over to the county treasurer, who shall place it to the credit of the current expense fund.
RCW 36.34.150