This study is designed to evaluate the effect of different methods of drinking water treatment on the occurrence of diarrhea among children living in squatter settlements in Karachi, Pakistan, and the marginal benefit of adding handwashing to water treatment. 260 households will receive a new product which combines flocculation with chlorination to produce clearer, less chemically contaminated drinking water. 260 households will receive dilute sodium hypochlorite, i.e. bleach to treat their water. 260 households will receive soap and encouraged to wash their hands regularly. 260 households will receive both soap and the combination flocculation/chlorination water treatment. 260 households will continue their standard water treatment and handwashing practices. The households will be visited each week for 9 months, and the episodes of diarrhea from each child in the household recorded. The rate of diarrhea between the groups will be compared. At the end of 9 months, households who were part of the standard habits and practice group will receive a water storage vessel and disinfectant.