30 ILCS 115/11
Upon determination by the Department that an amount has been paid pursuant to this Act in excess of the amount to which the county, municipality or taxing district receiving such payment was entitled, the county, municipality or taxing district shall, upon demand by the Department, repay such amount. If such repayment is not made within a reasonable time, the Department shall withhold from future payments an amount equal to such overpayment. If the appropriation from which such payment was originally made has not lapsed, the Department shall redistribute the amount of such payment to the county, municipality or taxing district entitled thereto. If the appropriation has lapsed, the repayment shall be deposited in the General Revenue Fund in the State Treasury.
30 ILCS 115/11