Investigations have shown sodium hypochlorite to be an effective disinfectant having broad applications. Although a number of other disinfectants (calcium hypochlorite, ozone, UV, solar disinfection) and treatment processes (filters, slow sand filtration) have been investigated, sodium hypochlorite appears to offer the best mix of low cost, ease of use, safety, and effectiveness in areas where there is enough water to drink and water is not excessively turbid. These characteristics are the reasons why most water treatment systems in the US and Europe have been using chlorine for disinfecting drinking water for nearly 100 years. The other disinfection methods noted above also effectively disinfect water and are useful in a number of settings.