In emergencies, safe drinking water is a priority to prevent disease. Chlorine is often used to treat drinking water, as it inactivates most bacteria and viruses that cause diarrheal disease and the remaining free chlorine residual (FCR) provides protection against recontamination in storage. For effective treatment, water should be dosed with enough chlorine to ensure that FCR is maintained for the length of storage time in the household. At the same time, levels high enough to exceed taste and odor acceptability thresholds should be avoided.
The goal of this document is to provide guidance on the assessment and interpretation of the parameters that influence tablet choice and the selection of specific size(s) of chlorine tablets which should (non-bindingly) be recommended for distribution in a particular emergency context.