70 ILCS 605/11-9
In any such proceeding, the defendant may, by counterclaim, set off or recoup any benefits which the defendant may have conferred upon the lands or other property in the plaintiff district or municipal corporation. If the plaintiff district has levied an annual maintenance assessment or if the plaintiff municipal corporation levies an annual tax for the purpose of repairing, maintaining or operating the drainage or levee work conferring such benefits, then, in such proceeding, the plaintiff may inquire into and determine the amount of the annual benefits which the defendant will receive from the repair, maintenance or operation of such work and the defendant may likewise set off or recoup the amount of annual benefits which the plaintiff will receive from the repair, maintenance or operation of drainage or levee work of the defendant.
70 ILCS 605/11-9