Upon the approval and final determination of the apportionment of estimated costs of extraordinary maintenance expenditures as provided in RCW 85.16.120 and 85.16.130, the board shall levy the amounts so apportioned against all the properties benefited and the amounts assessed against the state, county, cities and towns, and other municipal corporations benefited, and the auditor shall immediately prepare a completed roll thereof, which shall contain a copy of the order of the board approving and confirming said apportionment of estimated costs as finally determined and fixing and levying the assessments therefor, and shall deliver said roll to the treasurer for collection in accordance with the order of the board.