70 ILCS 3715/9
Any adjoining territory may be annexed to such water authority in the following manner: A written petition requesting such annexation and signed by a majority in numbers and in area owned of the owners of record of land in such adjoining territory shall be filed with the court in which such authority was created. A public hearing shall be had upon such petition after giving such notice by publication or posting, as the court may direct. At such hearing, any interested person shall be given an opportunity to be heard. If the court finds that the petition has been signed by the required number of landowners and there is no valid objection to such annexation, it shall enter an order annexing such territory.
Any territory within any such water authority which is upon the border thereof and which contains not less than twenty acres and which, if disconnected, will not result in the isolation of any part of such authority from the remainder thereof may be disconnected in the following manner: A written petition requesting such disconnection and signed by all the owners of record of land in such territory shall be filed with the court in which such authority was created. The water authority from which disconnection is sought shall be made a defendant and it or any taxpayer residing therein may appear and defend against said petition. If the court finds that the allegations of the petition are true and that the area of land is entitled to disconnection, it shall order the same disconnected. The disconnection of any such land shall not exempt it from taxation for the purpose of paying any indebtedness contracted by the authority prior to the filing of the petition.
70 ILCS 3715/9