Using a dynamic panel model of child anthropometrics from China, the effect of an in-yard water source on child health was measured. Changes in within-community averages of household access to in-yard water were used as the instrument for changes in access to in-yard water sources. Further, to address the concern of non-random placements of water projects, correlations between changes in disease symptoms and community-level changes in access to in-yard water sources were examined. It was found that access to in-yard water sources improved child health only when mothers were relatively well educated.