Clean water is used for drinking, cooking, cleaning, and personal hygiene. Cascading effects that clean water provides to reduce child mortality are very well understood. If you look at the mortality stats for ages 1-4 in Rwanda (https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/ghe-leading-causes-of-death) and assume reduction of both leading causes of death (lower respiratory infections − 38% and diarrhoeal diseases − 25%; 2019), then cutting mortality by 33% (ages below 5) sounds about right.
Clean water is used for drinking, cooking, cleaning, and personal hygiene. Cascading effects that clean water provides to reduce child mortality are very well understood. If you look at the mortality stats for ages 1-4 in Rwanda (https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/ghe-leading-causes-of-death) and assume reduction of both leading causes of death (lower respiratory infections − 38% and diarrhoeal diseases − 25%; 2019), then cutting mortality by 33% (ages below 5) sounds about right.