Chlorination systems normally consist of a tank of chlorine which is added to a water supply by a chemical pump. This addition can occur either at a reservoir or in-line, depending on the details of the water system in question. The chemical pump is usually linked to a flowmeter so that the amount of chlorine that is added depends on the amount of water that is used.
Chlorination can be used either to kill bacteria as a means of primary disinfection or to act as secondary disinfection to prevent re-contamination of water which has been cleared of bacteria by, for example, a UV system.
Chlorination systems are not normally installed at private residences but are very useful for larger or regulated sites.