20 ILCS 3110/7

The charges, fees or rentals established by the Authority for the use of any facilities acquired, constructed, completed, remodeled or equipped in whole or in part with the proceeds of the bonds issued as provided in this Act shall be sufficient at all times to pay the principal of and interest on the bonds and a proportion of the administrative expenses of the Authority as provided for by each lease, and such reserves as may be provided in the resolutions of issuance.