This 12-page half-size booklet gives an overview of the combined sewer systems in the Chicago area and explains how they work during rainstorms. It encourages our residents to become informed participants in the discussion about sewers, stormwater, and flooding, helping them understand this essential infrastructure.

Discover how the Tunnel and Reservoir Plan (TARP), often called the “Deep Tunnel,” protects Lake Michigan and the Chicago area’s waterways from pollution. This system involves deep, wide tunnels and large reservoirs that capture and store combined stormwater and sewage that might otherwise overflow into waterways.