Reliable and effective disinfection is a cornerstone of water and wastewater treatment, needed to protect public health. Most drinking water utilities are required to maintain a minimum disinfectant residual in the distribution system. This ensures adequate chemical was applied and remains in the system to kill pathogens. The most commonly used disinfectants — chlorine gas and bulk sodium hypochlorite — require operators to regularly handle these hazardous chemicals. Operators must be extensively trained in specialized procedures to ensure their safety and that of the community.