The indebtedness of any such district on contracts, or upon employment or for supplies, shall be paid by warrants on the district fund only, to be issued by the board upon allowed written claims. Such warrants shall be in form the same as county warrants, or as nearly the same as may be practicable; shall draw the legal rate of interest from the date of their presentation to the county treasurer for payment, and shall be signed by the chair and attested by the clerk: PROVIDED, That no warrants shall be issued in payment of any indebtedness of such district for less than the face or par value.
RCW 91.08.550
Public contracts and indebtedness-Interest rate on warrants: Chapter 39.56 RCW.