70 ILCS 605/11-8
Whenever a drainage district has a claim against another district or against a municipal corporation exercising drainage powers, or a municipal corporation exercising drainage powers has a claim against a drainage district for a portion of the cost of constructing, enlarging, improving, maintaining, repairing or operating any drainage or levee work, and the commissioners of the 2 districts or the commissioners and the corporate authorities of the municipal corporation, as the case may be, are unable to agree upon any or all of the terms of a written contract settling and adjusting the claim for benefits, then the proportionate share of the cost of such work to be borne by the benefited body shall be fixed by a court.
If the claim is made by a drainage district and the other district or the municipal corporation, as the case may be, was made a party to the proceeding authorizing the performance of the work, then the amount of such benefits shall be fixed in the assessment proceeding at the time and as a part of the hearing on the assessment roll. If the claim is made by a drainage district and the other district or the municipal corporation, as the case may be, was not made a party to the proceeding authorizing the performance of the work or if the claim is made by a municipal corporation, then the commissioners of the district performing the work or the corporate authorities of the municipal corporation performing the work, shall file a complaint in the circuit court of the county in which the defendant, or any part thereof, is situated or in any other court of competent jurisdiction. The pleadings and practice shall be as provided by the Civil Practice Law. A copy of the plans, profiles and specifications, together with a summary of the cost of the work done or an estimate of the cost of the work ordered to be done shall be attached to or filed with the complaint.
70 ILCS 605/11-8