Wash. Rev. Code § 41.37.280
A member who ceases to be an employee of an employer except by service or disability retirement may request a refund of the member's accumulated contributions. The refund shall be made within ninety days following the receipt of the request and notification of termination through the contribution reporting system by the employer; except that in the case of death, an initial payment shall be made within thirty days of receipt of request for such payment and notification of termination through the contribution reporting system by the employer. A member who files a request for refund and subsequently enters into employment with another employer prior to the refund being made shall not be eligible for a refund. The refund of accumulated contributions shall terminate all rights to benefits under RCW 41.37.190 through 41.37.290.
RCW 41.37.280