Using longitudinal data from records obtained from the Honduras Department of Public Health, paediatric diarrhoea and infant mortality rates were tracked over a six year period during which a large scale WASH intervention occurred in the Department of Colón, Honduras. Rates of paediatric diarrhoea and infant mortality from Colón were compared to national rates as well as a nearby department matched by using the Human Development Index. Both paediatric diarrhoea and infant mortality dropped significantly faster in Colón than in the control department and the national rates, supporting local assertions of the impact of such large scale interventions on childhood health and survival.