615 ILCS 50/5
Regional organizations, municipalities, political subdivisions, agencies or instrumentalities, and any other organization, association or individual desiring to use water from Lake Michigan and subject to allocation under this Act shall make application to the Department on forms provided by such agency which shall include a statement or finding relative to other sources of water or lack thereof within the area, the need for such allocation or apportionment of Lake Michigan water, the purpose or use to be made of the water so allocated, including an estimate of consumptive use, the point of diversion and the location of discharge after use, together with the route such discharge will follow to reach an identifiable main drain or stream, and whether such water will in any manner be treated or otherwise altered or changed prior to discharge and release from control by the applicant.
The Department in determining each allocation of water under this Act shall consider the water requirements of the Northeastern Illinois Metropolitan Region (specifically the counties of Cook, DuPage, Kane, Lake, McHenry and Will); the Department shall be guided by population, business and economic projections and requirements. The Department shall require that all feasible means reasonably available to the State and its municipalities, political subdivisions, agencies and instrumentalities shall be employed to conserve and manage the water resources of the region and the use of water therein in accordance with the best modern scientific knowledge and engineering practice.
615 ILCS 50/5