Improving water quality and natural habitat in the White River and our streams starts with looking at the sources of pollution. This brochure will explain CSOs and what can be done about them. To understand combined sewer overflows, let's first look at what a combined sewer system is. This system was adequate until the growing population created too much waste for the river to clean up naturally. Today, the system has been improved.
Pipes now carry the raw sewage and wastewater to a treatment facility instead of to the river.
However, when storms hit, excess water can fill the pipes and overburden the treatment facility, sending the sewage and storm water overflowing into the river. This is called a combined sewer overflow. Many older cities in the Great Lakes, Middle Atlantic and Northeast regions have combined sewer systems. There are approximately 950 communities in the U.S. with combined sewer overflows. In Indiana, slightly more than 100 communities have CSOs.