55 ILCS 5/5-11006
The provisions of this Division, and of any ordinance or other proceeding authorizing the issuance of bonds under the provisions of this Division, shall constitute a contract with the holders of such bonds, and any holder of a bond or bonds, or any of the coupons of any bond or bonds of said county, issued under this Division, may by action, mandamus, injunction or other proceeding, enforce and compel the performance of all duties required by this Division, including the making and collecting of sufficient charges and fees for service and use thereof, and the application of income and revenue thereof. In the event a trust agreement or agreements are executed and delivered to secure the payment of any such bonds, said trust agreement or agreements may prescribe by whom and on whose behalf such action may be instituted to compel performance and compliance therewith and of the duties and obligations required by this Division.
55 ILCS 5/5-11006