Wash. Rev. Code § 57.20.025
The board of commissioners of any district may by resolution provide for the issuance of refunding revenue bonds to refund outstanding general obligation bonds and/or revenue bonds, or any part thereof, and/or all outstanding local improvement district bonds, at maturity thereof, or before maturity thereof if they are subject to call for prior redemption or all of the holders thereof consent thereto. The total interest cost to the district over the life of the refunding bonds shall not exceed the total cost to the district which the district would have incurred but for such refunding over the remainder of the life of the bonds to be refunded thereby. The refunding bonds may be exchanged for the bonds to be refunded thereby, or may be sold in such manner as the board of commissioners deems to be for the best interest of the district, and the proceeds used, except as hereinafter provided, exclusively for the purpose of paying, retiring, and canceling the bonds to be refunded and interest thereon.
All unpaid utility local improvement district assessments payable into the revenue bond redemption fund established for payment of the bonds to be refunded shall thereafter when collected be paid into the revenue bond redemption fund established for payment of the refunding revenue bonds.
Whenever local improvement district bonds have been refunded as provided by RCW 57.20.018, or pursuant to this section, all local improvement district assessments remaining unpaid shall thereafter when collected be paid into the revenue bond redemption fund established for payment of the refunding revenue bonds, and the cash balance, if any, in the local improvement guaranty fund of the district and the proceeds received from any other assets owned by such fund shall be used in whole or in part as a reserve fund for the refunding revenue bonds or be transferred in whole or in part to any other funds of the district as the board of commissioners may determine. If any warrants are outstanding against the local improvement guaranty fund of the district at the time of the issuance of such refunding revenue bonds, the bonds shall be issued in an amount sufficient also to fund and pay such outstanding warrants.
The provisions of RCW 57.20.020 shall apply to the refunding revenue bonds issued under this title.
RCW 57.20.025
Part headings not law-Effective date-1996 c 230: See notes following RCW 57.02.001.