Illinois Statutes Chapter 65. Municipalities § 5/11-141-10.1. Annexation of territory including township sewerage system

(a) If a municipality annexes part or all of the territory in which a township operates a sewerage system that includes a sewage treatment plant or plants, and if the corporate authorities of the municipality do not operate a sewerage system that includes a sewage treatment plant or plants, the township shall be responsible for that portion of the sewerage system within the annexed territory. Any user fees attributable to the annexed territory shall remain with the township, unless, by agreement, the township assigns those fees.

(b) If a municipality annexes part or all of the territory in which a township operates a sewerage system that does not include a sewage treatment plant or plants, the authority responsible for operating the sewerage system within the annexed territory shall assume responsibility for that portion of the sewerage system within the annexed territory. Beginning upon the date of annexation, any user fees attributable to the maintenance and operation of the sewerage system shall be collected by the corporate authorities of the municipality.