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Lake Michigan Water Allocation

The Illinois Lake Michigan Water Allocation Program (Program) was developed to manage Illinois' diversion of water from Lake Michigan in response to a 1967 Supreme Court Decree amended in 1980. This Decree limits Illinois' diversion to 3,200 cfs based on a 40 year running average. The Program is authorized by the "LEVEL OF LAKE MICHIGAN ACT [615 ILCS 50] and is implemented by the IDNR/OWR's Lake Michigan Management Section (Chicago Office) using the Department's Part 3730 Rules "ALLOCATION OF WATER FROM LAKE MICHIGAN". These rules were updated in November, 2014.

Illinois' Lake Michigan Diversion is made up of three components, domestic water supply, direct diversion, and stormwater runoff. Domestic water supply is used to serve communities and industries within Cook, Lake, DuPage, Kane and Will Counties. Direct diversion consists of two main components, navigation and discretionary diversion. Diversion for navigation is used to provide a safe navigation depth in the Sanitary and Ship Canal system and for lockages at the Chicago River Controlling Works and the Thomas J. O'Brien Lock and Dam. Discretionary diversion is used to improve water quality in the canal system. Direct diversions are controlled through the Wilmette Pumping Station, the Chicago River Controlling Works and the Thomas J. O'Brien Lock and Dam. Stormwater runoff is water that has been diverted from the original Lake Michigan watershed (673 square miles) by the reversal of the Chicago and Calumet Rivers. Stormwater runoff numbers are calculated by the U.S. Army Corps of Engineers who under the terms of the Supreme Court Decree perform the annual diversion accounting for Illinois' Lake Michigan Diversion.

All diversions of water from Lake Michigan require authorization in the way of an allocation permit from the Chicago Office. The Chicago Office reviews all applications for new allocation permits and requests for modifications to existing allocation permits. The Chicago Office undertakes a complete review and reallocation of all existing allocation permits approximately every ten years.

All existing domestic water allocation permittees are required to submit an annual water audit form (LMO-2). The LMO-2 form details the amount of water used, sold and lost by a permittee in the past water year (October - September). The Chicago Office uses these forms to track individual user's compliance with the conditions of their allocation permits and to produce reports.

In addition to the annual LMO-2 form all direct diverters must submit a monthly pumpage form (LMO-3) which shows daily pumpage numbers and the amount of water sold to other Lake Michigan allocation permittees. A direct diverter is a permittee who has an intake structure on Lake Michigan or is the first Illinois user of water diverted outside of Illinois. The Metropolitan Water Reclamation District of Greater Chicago submits monthly reports detailing Lake Michigan water used for Direct Diversion. All data collected is submitted to the Corps of Engineers to be used in their diversion accounting.


  • 2022 Stantec Allocation Report

Water Rate Surveys

  • 2015 Lake Michigan Water Rate Survey
  • 2010 Lake Michigan Water Rate Survey
  • 2005 Lake Michigan Water Rate Survey

LMO-2 Report Summary Tables

  • 2009 Report Summary Table (PDF)
  • 2010 Report Summary Table (PDF)
  • 2011 LMO-2 Report Summary Table (PDF)
  • 2012 LMO-2 Report Summary Table (PDF)
  • 2013 LMO-2 Report Summary Table (PDF)
  • 2014 LMO-2 Report Summary Table (PDF)
  • 2015 LMO-2 Report Summary Table (PDF)
  • 2016 LMO-2 Report Summary Table (PDF)
  • 2017 LMO-2 Report Summary Table (PDF)


  • Permitting on Lake Michigan Presentation  2023
  • Lake Michigan Water Conservation Goals and Objectives 2010
  • Administrative Rule, Chapter 1, Sec 3730 Allocation of Water from Lake Michigan (PDF)
  • 2014 Water Conservation and Efficiency Program Review (DOC) (PDF)
  • Five Year Review of Illinois' Water Management and Conservation and Efficiency Programs - 2014
  • Six Year Review of Illinois' Water Management and Conservation and Efficiency Programs - 2015 
  • Seventh Year Review of Illinois’ Water Management, Conservation and Efficiency Program – 2016
  • Lake Michigan Water Allocation Newsletter, 2014 Edition
  • Lake Michigan Allocation Program October 20, 2021 [ Video ]
  • Lake Michigan Allocation Program October 22, 2021 [ Video ]
  • Lake Michigan Allocation Program December 7, 2021 [ Video ]
  • Lake Michigan Allocation Program December 9, 2021 [ Video ]

The U.S. Army Corps of Engineers, Chicago District's Lake Michigan Diversion homepage allows anyone to look at or download the Corps' latest reports on Illinois diversion. They are the official keepers of certified reports of our diversion.

Allocation Objectives

The importance of wise, long-term water resource planning and the large investments that must be made to secure new water supply sources requires that the objectives of an allocation program clearly address the problems to be solved. In Illinois' case, the objectives must also address the specific requirements of the U.S.:

  • To make the greatest amount of Lake Michigan water available for domestic water supply.
  • To use Lake Michigan water allocations as a tool to preserve groundwater resources for communities in northeastern Illinois who will not have access to a Lake Michigan water supply.
  • To make long-term allocations so that communities receiving an allocation for the first time can secure the needed financing to construct regional water distribution systems.
  • To carefully consider the competing needs of all water users in the region so that allocations promote the efficient development of water supplies in the region in light of long range needs and objectives.
  • To require all users of Lake Michigan water to conserve and manage this resource.

Allocation Process

A successful water allocation program must combine a technically defensible methodology with an administrative process that follows legally defensible procedures and treats all applicants fairly. To achieve this goal, Illinois' allocation process consists of the following key elements:

  • An active public participation program.
  • An identification of available water supply sources.
  • A long-range water demand forecasting methodology.
  • Formal allocation hearings on all requests.
  • Issuance of an Allocation Order.
  • Ongoing monitoring of water use and consumption by all permittees.
  • Formal process to make adjustments in allocations.


Any questions or requests concerning Illinois' Lake Michigan Water Allocation Program can be directed to the Chicago Office at (312) 793-3123. You can also email Russ Flinchum.

The Chicago Office is located at:

Michael A. Bilandic Building
160 N. LaSalle Street, Suite S-703
Chicago, IL 60601