Irrigation dams enable farmers to harness substantial water resources. However, their use consumes finite water supplies and recycles agricultural water pollutants back into river systems. This paper examines the net effect of irrigation dams on infant mortality in South Africa. It relies on both fixed effects and instrumental variables approaches to counteract potential bias associated with non-random dam placement, with the latter approach predicting dam placement based on geographic features and policy changes. The analysis reveals that additional irrigation dams within South Africa's former homeland districts after Apartheid increased infant mortality by 10–20 percent. I then discuss and evaluate possible channels. Dam-induced increases in agricultural activity could increase water pollution and reduce water availability, and I provide supporting evidence that both channels may contribute. These results suggest a potential trade-off between the health costs of agricultural water use and the economic benefits of increased agricultural production.