55 ILCS 5/5-32013
The ordinance provided for in this Division shall provide that the aggregate amounts assessed in each individual assessment shall be divided into installments not more than 10 in number. Such division shall be made so that all installments shall be equal in amount except that all fractional amounts shall be added to the first installment so as to leave the remaining of the aggregate equal in amount and each a multiple of $100. The first installment shall be due and payable on January 2 next, after the date of the first voucher issued on account of construction work done, and the second installment one year thereafter and so on annually until all installments are paid. The Committee shall file in the office of the Clerk of the Circuit Court in which such assessment was confirmed a certificate signed by its secretary of the date of the first voucher and the amount thereof within 30 days after the issuance thereof. All installments shall bear interest as hereinafter provided until paid at the rate of not to exceed 7% annually. Interest on assessments shall begin to run from the date of the first voucher issued on account of construction work done. The interest on each installment shall be paid as follows: On January 2, next succeeding the date of the first voucher as certified the interest accruing up to that time on all unpaid installments shall be due and payable with the installment, and thereafter the interest on all unpaid installments then payable shall be payable annually and be collected therewith. In all cases the County Collector, whenever payment is made on any installment, shall collect interest thereon up to the date of such payment whether the payment be made at or after maturity. Any person may at any time pay the whole assessment against any lot, piece or parcel of land or any installment thereof with interest as herein provided up to the date of the payment.
55 ILCS 5/5-32013