Does gaining a more proximate water source improve a child’s attendance in school and
consequent educational attainment? Policymakers and IGOs alike argue that time savings from
improved water access create educational opportunities children, especially girls. While this
logic motivates development projects around the world, these claims have not been tested
rigorously. Moreover, there are reasons to believe that pro-son bias leads households to
redistribute time saved from improved water access unequally, allowing boys to attend school
and not girls. We test these competing arguments by evaluating the effect of changes in
proximity to water on children’s educational outcomes in Uganda and the Kagera region of
Tanzania. Contrary to the conventional narrative, we find that water access improves
educational attainment only among boys. Consistent with the argument that pro-son bias
motivates this sex-based difference in the effect of water access, we find that the educational
gains are greatest where girls and boys share water-harvesting duties.