65 ILCS 5/9-3-33
If upon final settlement with the contractor for the construction of any improvement and after paying all costs of levying, collecting and making the assessment, which amount shall not under any circumstances exceed 12% of the estimated contract price, and all bonds and interest thereon issued, as in this Division 3 provided, except those bonds and interest coupons not presented for payment, although called and for which funds are available and reserved, within the period of time specified in Section 9-1-5, there shall be any surpluses remaining in the special assessment fund, the corporate authorities of such municipality shall at once cause a rebate to be declared upon each lot, tract or parcel of real estate assessed of its pro rata proportion of such surplus. Such rebate shall be paid to the owner of record of each such lot, block, tract or parcel at the time of the declaration of the rebate. Should any additional funds be collected after the original rebate is declared, the municipality shall not be required to declare a supplemental rebate for 5 years from the date the original rebate is declared. The municipality may deduct for its costs and expenses for declaring and making any rebate not more than 5% of the amount declared to be rebated. All surpluses shall remain in the special assessment fund until after full payment of all bonds and vouchers issued in anticipation of the collection of the assessment, and there shall be no rebate until all such bonds and vouchers have been paid in full, both as to principal and interest, except those bonds and interest coupons not presented for payment, although called and for which funds are available and reserved, within the period of time specified in Section 9-1-5. The corporate authorities shall cause to be kept and exhibited publicly in the office of the clerk of such municipality, an index of all special assessment accounts or warrants upon which a rebate is due and payable and upon proper proofs the same shall be repaid to the persons entitled thereto.
65 ILCS 5/9-3-33