Wash. Rev. Code § 35.45.155
Any city or town having issued one or more installment notes pursuant to RCW 35.45.150 may refund all of such notes or the principal thereof then outstanding payable from any one local improvement district fund by the issuance of local improvement district bonds pursuant to chapter 35.45 RCW and by the payment into the city or town fund or funds holding such notes the then outstanding principal amount of such notes plus the interest thereon accrued to the date of such refunding. The bonds shall be payable from the same local improvement district fund from which such notes were payable; shall be payable no later than the final payment date of the notes being refunded; shall be in the same total principal amount as the outstanding principal amount of the notes being refunded less any sums in the local improvement district fund the city or town applies to the redemption of such notes; and shall be sold at not less than par plus accrued interest to date of delivery. Any interest payable on the bonds in excess of the interest payable on assessment installments payable into the local improvement district fund shall be paid from the general fund of the city or town in accordance with RCW 35.45.065. The principal proceeds and interest accrued to date of delivery of the bonds shall be paid into the local improvement district fund and the notes shall be redeemed on that date. The city or town shall pay all costs and expenses of such refunding from moneys available therefor.
RCW 35.45.155