Chlorine is the most commonly used water disinfectant, and it is often the chemical of choice for treatment of such water issues as hydrogen sulfide, iron, and manganese.

Chlorine is a powerful oxidant and is in disinfectants, as well as an essential reagent in the chemical industry. As a common disinfectant, chlorine compounds are used in swimming pools to keep them clean and bacteria-free. In the upper atmosphere, molecules containing chlorine such as chlorofluorocarbons have been implicated in the destruction of the ozone layer.

Chlorine, along with chloramine, a blend of chlorine and ammonia, is the most commonly used disinfectant in US water systems. Since the early 1900s it has been the preferred disinfectant of most public water suppliers.

Basic information about chlorine:

Chlorine Demand: the amount of chlorine required to react with impurities to be treated (bacteria, iron, manganese, ammonia, etc.).

Sodium Hypochlorite: Liquid Chlorine.

Calcium Hypochlorite: Chlorine in Solid Form.

Laundry Bleach: 5.25% sodium hypochlorite.

Removing Chlorine from water. Chlorine is relatively easy to remove. The most common and the most effective method is carbon filtration. Most carbon filters, even the small inexpensive ones, do a decent job of chlorine removal. KDF, a redox medium used in shower filters and drinking water filters, is also an effective and long-term chlorine reducer, especially when used with carbon. Ascorbic acid (Vitamin C) also removes chlorine and is widely used in residential shower filters.