The effects of water supply on infant and childhood mortality: a review of historical evidence.

The provision of clean water is mentioned as an important factor in many studies dealing with the decline of mortality in Europe during the late nineteenth and early twentieth centuries. In developing countries too, improved water supply is assumed to have a strong impact on mortality. When studying the effect of water supply on public health, researchers are confronted with many methodological problems. Most of these also apply to historical studies of the subject. We review the evidence from this historical research, taking into account the methodological problems observed in contemporary impact evaluation studies, and we use more refined data from the Dutch city of Tilburg, enabling us to overcome many of these shortcomings. Finally, we discuss some factors which may explain why we failed to discover an effect of the availability of piped water on the level of childhood mortality.