A small amount of fluoride is added to help in the prevention of tooth decay. The treatment process used for Illinois-American's well sources in Pekin and Peoria include disinfection. Fluoride is added to all sources. Iron and manganese removal, plus corrosion control are sometimes necessary. Iron treatment .
Water is treated with chlorine which oxidizes the iron, which means it makes it form a solid.
Water then flows through sand filters which remove the iron. Manganese is removed by similar means, often with potassium permanganate as the oxidant. All water is chlorinated at the end of the treatment process to ensure that the required chlorine residual is maintained in the distribution system. Numerous precautions are taken to ensure that high-quality water is maintained throughout the many miles of pipeline in the company's distribution system. In order to maintain a bacteriologically safe distribution system, it is necessary to maintain a chlorine residual throughout the underground water mains.