Benefits trickling away: the health impact of extending access to piped water and sanitation in urban Yemen

This article investigates the impact of extending piped water supply and sanitation on health outcomes in urban Yemen using a combination of quasi-experimental methods and results from microbiological water tests. Variations in project roll-out allow separate identification of water and sanitation impacts. The results indicate that access to piped water supply worsens health outcomes when water rationing is frequent, which appears to be linked to the build-up of pollution in the network. When water supply is continuous no clear health benefits are found compared to traditional urban water supply through water vendors, but connections to piped sewers can then lead to health improvements. The findings suggest that investments in piped water supply should not be made when reliability of water cannot be guaranteed.