65 ILCS 5/11-71-6

The provisions of this Division 71 and of any ordinance or other proceeding authorizing the issuance of bonds under this Division 71 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 such municipality, issued under this Division 71, may either by an ordinary civil action, mandamus, injunction or other proceeding, enforce and compel the performance of all duties required by this Division 71, including the making and collecting of sufficient charges and fees for service and use thereof, and the application of income and revenue thereof.