What are the health benefits of a constant water supply? Evidence from London, 1860-1910

In this project, we investigated the health benefits of a 25-year improvement in water quality as London transitioned from a system of intermittent water supply (IWS) to a constant water supply (CWS). We assessed the mortality effects of London’s transition from an intermittent to a constant water supply between 1871 and 1910, as the proportion of London households with access to CWS (24 hours a day, 7 days a week) rose from less than 20 to nearly 100 percent. We used waterborne disease mortality data for the Registration County of London corrected for institutional deaths by William Luckin, Graham Mooney and Andrea Tanner as part of their Mortality in the Metropolis, 1860-1920 project. We combined this with data on constant service and population shares for London's eight water companies, census data on district level population and demographics, and Registrar General data on deaths from non-waterborne causes.