The agency says the changes are necessary because an increasing number of people are coming into direct contact with the water through kayaking, canoeing, boating, jet and water skiing and other forms of recreation.
EPA is directing the Illinois Pollution Control Board to adopt new or revised water quality standards for the North and South Branches of the Chicago River, the North Shore Channel, the Cal-Sag Channel and the Little Calumet River.
Since 2007, EPA has repeatedly recommended that Illinois upgrade water quality standards for the Chicago waterway system. If the board does not act, the Clean Water Act authorizes EPA to do so.
To attain the new water quality standards, the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) will likely be required to disinfect sewage discharged into the waterway system from its North Side and Calumet treatment plants. MWRDGC ceased disinfection at these facilities in the mid-1980s.
For information on the determination and to view a map showing the affected segments of the Chicago Area Waterway System, go to http://www.epa.gov/region5/chicagoriver/