Combined Sewer Overflows
Combined Sewer Overflows (CSOs) remain a key problem across the Great Lakes region. CSOs occur when pipes carrying both sanitary sewage and rainwater overflow into streams, rivers and lakes during heavy rains. The Great Lakes account for 70 percent of CSOs in the United States, according to the International Joint Commission. Detroit is the leading source of overflows in the Great Lakes, but it’s a problem across the region during heavy rains. A nearly 7-inch rainfall over several days in 2008 resulted in the release of 11 billion gallons of combined sewer overflow into Lake Michigan.
Viewer Tip: Conserving water at home can help lower the load on our sewer systems. Consider installing low-flow toilets and other appliances to reduce sanitary sewage flows from your home. Look for appliances labeled with EPA’s Water Sense seal, which indicates water-efficient products. Visit www.epa.gov/watersense for more information.
Learn more about about CSOs at www.greatlakes.org/Page.aspx?pid=454.
Seasons: Spring, Summer, Fall, Winter
This information is provided by the Alliance for the Great Lakes. Learn more at www.greatlakes.org.
(Sources: International Joint Commission 14th Biennial Report
on Great Lakes Water Quality http://www.ijc.org/php/publications/pdf/ID1631.pdf
Environmental Protection Agency study on CSOs and climate change: http://www.epa.gov/ord/npd/pdfs/cso-extrevdraft-mar07.pdf, Alliance for the Great Lakes)
