Chicago Water Department Facilities
The water's journey begins two miles off the Chicago shoreline in Lake Michigan at water intake structures called "cribs". These cribs, located in 35-foot deep water, have served the Chicagoland area since their construction about 100 years ago.

Lake Michigan water enters the Harrison Dever Intake Crib through openings 20 feet below the lake's surface. The water rises around the outside of a large pipe inside the crib then flows through a 20 foot diameter tunnel to the James W. Jardine Water Purification Plant, the largest water treatment plant in the world - located just north of Chicago's Navy Pier.

Upon reaching the plant, the water is pumped to a height of about 20 feet above lake level. Water flows, by gravity, through the chemical application channels and basins of the plant. In the first treatment channel, chemicals like alum are added to collect and remove impurities from the water. Then, powdered activated carbon is added as necessary to improve taste and remove odors, enhancing the quality of the water.