55 ILCS 5/5-32048: Vouchers.

From time to time as the work progresses the contractor shall be issued vouchers in payment therefor, and if not converted to bonds, the vouchers so issued shall be called for payment in numerical order and are to be paid from installments 2 through 10, as collected. Vouchers issued for work done including engineering and the cost of making, levying and collecting the special assessment are to be paid pro rata against the first installment of the special assessment, as collected.