A Combined Sewer is a type of sewer system that collects both sanitary sewage and stormwater runoff in a single pipe system. Combined Sewer Systems can cause serious water pollution problems due to combined sewer overflows, which are caused by large variations in flow between dry and wet weather conditions. This type of sewer design is no longer used in new construction, but many of the older areas still utilize this type of system. The Village of Lemont has dedicated itself to going into some of the more historic areas and separating the combined systems into separate, sanitary and storm systems.
Illinois EPA Division of Water Pollution Control
Annual Facility Inspection Reports