Household water treatment: Evidence on effectiveness and cost-effectiveness

A recent Cochrane review of water quality interventions, including household water treatment, to prevent diarrhoeal disease. Thirty trials covering over 53,000 participants met the inclusion criteria. Differences between the trials limited the comparability of results and pooling by meta-analysis. In general, however, the evidence suggests that interventions to improve the microbiological quality of drinking water are effective in preventing diarrhoea both for populations of all ages and children less than five years old. Subgroup analyses suggest that household interventions are more effective in preventing diarrhoea than interventions at the water source. Effectiveness was positively associated with compliance but not with ambient water quality. Effectiveness was not conditioned on the presence of improved water supplies or sanitation in the study setting, and was not enhanced by combining the intervention to improve water quality with other common environmental interventions intended to prevent diarrhoea.

Using effectiveness data from the Cochrane review and cost data from programme implementers and World Health Organization (WHO) databases, we conducted a cost-effectiveness analysis to compare conventional source- and four types of household-based interventions to improve the water quality for preventing diarrhoeal disease. Measured against international benchmarks, source- and household-based interventions were generally cost effective or highly cost effective even before the estimated saving in health costs that would offset the cost of implementation. Household-based chlorination was the most cost-effective where resources are limited; household filtration yields additional health gains at higher budget levels. Flocculation/disinfection was strongly dominated by all other interventions; solar disinfection was weakly dominated by chlorination.