70 ILCS 3405/18
In case any surface water protection district organized hereunder is coterminous with or includes within its corporate limits any pre-existing city, village or incorporated town authorized to provide protection from surface water damage and to regulate the prevention and control of surface water within such city, village or incorporated town and to levy taxes for any such purposes, then such city, village or incorporated town shall, within one year after it is included within the district, cease to exercise any such powers as necessarily conflict with the powers to be exercised by such district in respect to such surface water protection and regulation within the surface water protection district. Such city, village or incorporated town shall not thereafter own, maintain, manage, control or have an interest in any surface water protection facilities located within the corporate limits of the surface water protection district, except curbs and gutters in streets and except as otherwise provided in this Act. Where in any case any pre-existing city, village or incorporated town owns and is in fact operating and maintaining surface water protection facilities located within the corporate limits of a surface water protection district organized under this Act, such city, village or incorporated town shall be paid and reimbursed for the reasonable value of any such existing facilities in the manner provided for by this Act. The terms of payment shall provide for reimbursement in full within not less than twenty years from the date of such agreement.
70 ILCS 3405/18