The City uses chlorine as the primary disinfectant to maintain a disinfectant level in the distribution system. The Yellowstone River has organic compounds that react with disinfectants and produce by-products. In excessive quantities, these by-products may have harmful health effects. It should be noted that any harmful health effects caused by disinfection by-products are small compared with the health risks associated with inadequate disinfection. Secondary Contaminants and Other Parameters Secondary contaminant levels represent reasonable goals for drinking water quality and provide a guideline for public water suppliers.
Secondary contaminants affect mainly the aesthetic qualities of drinking water.
If present at high concentration levels, health problems might exist.