The United Nations’ Sustainable Development Goals aim to provide universal access to water, sanitation, and hygiene (WASH) globally by 2030. However, over 844 million people worldwide still lack access to basic drinking water, while more than 2.3 billion people lack access to basic sanitation. Furthermore, millions of girls are forced to abandon their studies each year due to menstrual hygiene issues, and hygiene-related illnesses like diarrhea and pneumonia continue to be the leading cause of death for children under age five. Shockingly, more children die from WASH-related causes than from malaria, AIDS, and tuberculosis combined. DevInsights has implemented research and evaluation in several WASH projects, notably a large-scale sanitation improvement project in schools. We analyzed the impact of improved sanitation facilities on student health and school attendance. Our work has informed nationwide hygiene promotion campaigns, contributing to reductions in waterborne diseases and increased school enrolment.