Metropolitan Water Reclamation District of Greater Chicago services

The mission of the countywide stormwater management program is to provide Cook County with effective rules, regulations, and projects that will reduce the potential for stormwater damage to life, public health, safety, property and the environment. Nineteen stormwater management goals have been developed by the District for the CCSMP. The goals extend from protecting new and existing development from flooding to preventing the loss of water quality and habitat.A brochure describing the District"s countywide stormwater management program can be found here.The authority for general supervision of stormwater management in Cook County was conveyed to the District pursuant to the passage of Public Act 93-1049 (Act) by the Illinois State Legislature on November 17, 2004. A summary of the Act can be found here.

Despite the reversal of the Chicago River, and even the construction of the largest wastewater treatment plant in the world, contaminants continued to accumulate in the rivers, canals, and Lake Michigan. The persistence of the problem was due mainly to the fact that Chicago and many of the older suburbs are served by combined sewers, in which both sanitary and storm flow are conveyed through the same pipes.As the area developed and more land was paved, the amount of rain water entering the sewer system dramatically increased. During rain events, the sewer system and treatment plants could not accommodate the additional flow, and combined sewage would overflow to the local waterways over 100 days per year. Within the combined sewer areas there were over 600 outfalls that released polluted combined sewer overflows (CSOs) into the waterways. During particularly large storms, the rivers were forced to reverse to their natural direction, releasing raw sewage into the lake.