70 ILCS 2605/7aa
The sanitary district has the power and authority to prevent the pollution of any waters from which a water supply may be obtained by any city, town or village within the district. The sanitary district acting through the executive director has the power to commence an action or proceeding in the circuit court in and for the county in which the district is located for the purpose of having the pollution stopped and prevented either by mandamus or injunction. The court shall specify a time, not exceeding 20 days after the service of the copy of the petition, in which the party complained of must answer the petition, and in the meantime, the party be restrained. In case of default in answer or after answer, the court shall immediately inquire into the facts and circumstances of the case and enter an appropriate judgment order in respect to the matters complained of. An appeal may be taken from the final judgment in the same manner and with the same effect as appeals are taken from judgments of the circuit court in other actions for mandamus or injunction.
70 ILCS 2605/7aa