847-853-7535 (24 hours)
200 Lake Avenue
Wilmette, IL 60091
The Wilmette Water Plant is a surface water treatment facility located on the shores of Lake Michigan. Providing water for the nearly 100,000 residents of Wilmette, Glenview and Prospect Heights, the plant pumps an average of 13 million gallons of water per day (MGD), with a peak of 31 MGD during summer. The Water Plant has a staff of 18 employees.
The water treatment process begins with the intake of raw water from Lake Michigan. Low lift pumps deliver water into the plant where it is treated with chlorine for disinfection, alum for clarification, fluoride for dental health and activated carbon for taste and odor control. Approximately one teaspoon of chemicals is used for every 100 gallons of water treated.
Following this chemical addition, water flows by gravity into mixing/settling basins where gentle mixing, or “flocculation”, enhances the formation of “floc” particles with the alum. These floc particles collide with and bond to suspended natural silt and clay particles from the Lake, causing them to “settle out” in the settling basins. Ninety percent of all solid materials that enter the plant are removed in the sedimentation step.
Following sedimentation, the water is filtered through rapid sand filters. Here, the filtered water receives an additional dose of chlorine as well as ortho-polyphosphate — to inhibit corrosion of the distribution piping — before entering the Water Plant’s underground clearwell/reservoirs. The entire trip through the treatment processes takes about eight hours (see treatment schematic).
Once in the finished water storage tanks, the water is delivered to the distribution system using high lift pumps, filling the Village’s 4.0 million gallon (MG) standpipe and 3.0 MG reservoir/pumping station. From the distribution system, it meets the water needs of the residents of Wilmette , Glenview and Prospect Heights — providing the pure sparkling water that the Village’s customers have come to expect.
Residents who have questions regarding the operations of the Plant or who want to report an emergency should call the 24 hour general information line at (847) 853-7535. The Wilmette Water Plant also has a certified laboratory staffed by a chemist. Any residents with a question concerning the quality of their water should contact the plant laboratory at (847) 853-7532.