70 ILCS 2305/8.1
Every such sanitary district shall also have the power to lease to others for any period of time, not exceeding 50 years, upon such terms as its board of trustees may determine, any real estate, right-of-way, or privilege, or any interest therein, or any part thereof, acquired by it which is in the opinion of the board of trustees of such sanitary district, no longer required for its corporate purposes or which may not be immediately needed for such purposes, and such leases may contain such conditions and retain such interests therein as may be deemed for the best interest of such sanitary district by such board of trustees; also any such sanitary district shall have the right to grant easements and permits for the use of any such real property, right-of-way, or privilege, which will not in the opinion of the board of trustees of such sanitary district, interfere with the use thereof by such sanitary district for its corporate purposes, and such easements and permits may contain such conditions and retain such interests therein as may be deemed for the best interests of such sanitary district by such board of trustees.
70 ILCS 2305/8.1