70 ILCS 2405/7.7
If one or more persons pay for building a sewer to be dedicated to the sanitary district as a public sewer, and if the sewer will, in the opinion of the board of trustees, be used for the benefit of property whose owners did not contribute to the cost of the sewer's construction, the board of trustees may provide for reimbursement of some or all of the expenses of the persons who paid for the sewer as provided in this Section. The board of trustees may, by contract, agree to reimburse the persons who paid for the sewer, in whole or in part, for a portion of their costs. The reimbursement shall be made from fees collected from owners of property who did not contribute to the cost of the sewer when it was built. The contract shall describe the property that, in the opinion of the board of trustees, may reasonably be expected to benefit from the sewer and shall specify the amount or proportion of the cost of the sewer that is to be incurred primarily for the benefit of that property. The contract shall provide that the sanitary district shall collect the fees charged to owners of property not contributing to the cost of the sewer at any time before the connection to the sewer by the respective properties of each owner. The contract may provide for the payment of a reasonable amount of interest or other charge on the amount expended in completing the sewer, with interest to be calculated from and after the date of completion of the sewer.
70 ILCS 2405/7.7