60 ILCS 1/205-145

All revenue derived from the operation of a waterworks system or sewerage system, or combined waterworks and sewerage system, constructed, acquired, extended, or improved to serve a particular locality shall be set aside as collected and shall be deposited in a special fund of the township. That fund shall be used only (i) to pay the cost of operating and maintaining the waterworks system or sewerage system, or combined waterworks and sewerage system, constructed, acquired, extended, or improved to serve a particular locality, (ii) to provide an adequate depreciation fund, and (iii) to pay the principal and interest on the bonds issued by the township under Sections 205-130 through 205-141 for the purpose of constructing, acquiring, extending, or improving the system.