In drinking water systems, swimming pools, etc., sodium hypochlorite is widely used for chlorination. Hypochlorites are an alternative to chlorine gas, which is difficult to handle in many contexts. Also, accidents involving chlorine gas are more serious than accidents involving hypochlorites.[citation needed] Chlorination usually produces small quantities of harmful byproducts. Hypochlorites are very similar to chlorine gas in this regard.

Sodium hypochlorite solutions have been used to treat dilute cyanide wastewater, such as electroplating wastes. In batch treatment operations, sodium hypochlorite has been used to treat more concentrated cyanide wastes, such as silver cyanide plating solutions.