65 ILCS 5/11-135-7
Such commission may construct, maintain, alter and extend its water mains as a proper use of highways along, upon, under and across any highway, street, alley or public ground in the state, including highways within a municipality, but so as not to inconvenience the public use thereof, and such commission may construct, maintain and operate any conduit or conduits, water pipe or pipes, wholly or partially buried or otherwise in, upon and along any of the lands owned by the State of Illinois and under any of the public waters therein. However, the right, permission and authority hereby created shall be subject to all public rights of commerce and navigation and the authority of the United States in behalf of such public rights and also the laws of the State of Illinois to regulate and control the same. Notice shall be given to the highway authorities of any municipality, county, township, road district or township district in which such highway, street or public way may be situated at least 60 days before any construction or installation work in such highway or street shall commence. All laws and ordinances pertaining to such work for the protection of the public and of public property shall be complied with except that no fee may be charged such commission for the construction or installation of such facilities in such public places.
65 ILCS 5/11-135-7