Storm sewers are pipes found beneath our city streets. They handle stormwater, such as rain and melting snow.
Rainwater flows into storm drains--the openings that you often see along curbs. After water enters the storm sewers, it flows directly to rivers, lakes, or bays. The water is not treated, or cleaned, before it goes to a waterway. That’s why it’s a big problem when ooze mixes with rain.
Rainwater picks up all kinds of trash, dirt, and chemicals when it moves across the ground. Polluted stormwater moves into the sewers and flows straight to a lake, river, or bay.
Workers pose in the huge sewer pipes below Chicago streets. Storm sewers catch rain and melting snow.
Photo: Chicago Public Library