Globally, more than 1 million children under 5 die each year from diarrheal disease. Contaminated drinking water, poor hygiene, and the lack of sanitation facilities are leading causes of this problem.

Diarrhea is the second largest cause of mortality in children under 5 after respiratory infections, accounting for almost 19% of child deaths in developing countries. Even when episodes are not fatal, chronic diarrhea in early childhood can contribute to malnutrition, reduced resistance to infection, stunted growth, and worse performance in school.

Improving water sources is insufficient, as unhygienic water collection and unsafe storage practices often lead to recontamination, making it difficult to ensure that water is actually safe when people drink it.

An early study evaluated the effectiveness of protecting springs in rural areas where piped water is not feasible or cost-effective. This study found that spring protection reduced source contamination by 66%, but that contamination of household drinking water only decreased by 24% as a result of unsanitary water collection and storage. The researchers, then, sought a solution that would protect drinking water from recontamination.

The research team next investigated strategies to encourage household chlorination. Chlorine kills 99.99% of harmful bacteria, keeps water free from contamination for up to 72 hours, and reduces the incidence of diarrhea by 40%. A randomized controlled trial was conducted in Kenya to compare chlorine dispensers to other chlorination options.

The researchers found that 50-61% of people adopted the chlorine dispenser system compared with only 6-14% in the control group, or an approximately 40 percentage point increase. Adoption was sustained over time.