65 ILCS 5/11-125-2
For the purpose of establishing or supplying waterworks and to purchase, extend, improve and operate waterworks, each city or village may go beyond its corporate limits and acquire and hold property by purchase or otherwise, and also may take and condemn all necessary property therefor, in the manner provided for the taking or damaging of private property for public uses, including any land now used for highway purposes in or near any basin proposed to be flooded by the construction, extension or improvement of any lake by any city or village of this state, for water supply purposes, provided the highway is capable of being rerouted, raised or otherwise revised and maintained in use and that the city or village requiring such reconstruction shall either perform the necessary reconstruction work or pay the full cost thereof to provide a highway of equal value and usefulness to that existing before such work is required, or provided the highway has been vacated by order of the highway authorities having a jurisdiction over said highway. The jurisdiction of the city or village to prevent or punish any pollution or injury to the stream or source of water, or to waterworks, extends 20 miles beyond its corporate limits, or so far as the waterworks may extend.
65 ILCS 5/11-125-2