A water purification process in which chlorine is added to water for disinfection, for the control of present microorganisms. It is also used in the oxidation of compound impurities in water.Chlorination is needed for raw water sources such as groundwater, rivers, and lakes that possess organic matters which are extremely harmful to human health and causes diseases in humans. Pathogens are the primary organisms responsible for most disease transmissions through water supply systems, giving rise to waterborne diseases to those who consume it. There are several disinfection choices that work terrifically in preventing the spread of pathogens by inactivating them. Chlorination, along with filtration, sedimentation, and coagulation produces water that provides security for public consumption.