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Village Water Source and Treatment Process
Where our water comes from
The water used by the Village of Tinley Park is surface water from Lake Michigan. Tinley Park buys its water from the Village of Oak Lawn, which in turn gets its water from the City of Chicago. The Environmental Protection Agency (EPA) has found that the quality of Lake Michigan has improved dramatically throughout the last 20 years. Lake Michigan, by volume, is the second-largest of the Great Lakes and the only one located entirely in the United States. At the present time, the City of Chicago and 118 communities receive water from Lake Michigan.

Treating our water
The treatment process consists of three main steps:
  1. First, raw water is drawn from Lake Michigan and sent to an aeration tank, which allows for oxidation of the high iron levels that are present in the water. The water then goes to a mixing tank where polyaluminum chloride and soda ash are added. The addition of these substances causes small particles to adhere to one another (called floc), making them heavy enough to settle into a basin from which sediment is removed.
  2. Chlorine is then added for disinfecting. At this point, the water is filtered through layers of fine coal and silicate sand. As smaller, suspended particles are removed, turbidity disappears and clear water emerges. Chlorine is added again as a precaution against any bacteria that may still be present. (The Village carefully monitors the amount of chlorine, adding the lowest quantity necessary to protect the safety of your water without compromising taste.)
  3. Finally, soda ash (used to adjust final pH and alkalinity), fluoride (used to prevent tooth decay) and a corrosion inhibitor (used to protect distribution system pipes) are added before the water is pumped and sanitized to underground reservoirs, water towers and into your home or business.

Water Quality Report


Contact us
For additional information about the Village's water source or its water treatment process, please contact the Tinley Park Public Works Department at (708) 444-5500.