EHS 2018 special: London’s mortality decline – lessons for modern water policy

Werner Troeksen (University of Pittsburgh)
Nicola Tynan (Dickinson College)
Yuanxiaoyue (Artemis) Yang (Harvard T.H. Chan School of Public Health)

The United Nations Sustainable Development Goals aim to ensure access to water and sanitation for all. This means not just treating water but supplying it reliably. Lives are at stake because epidemiological research shows that a reliable, constant supply of water reduces water-borne illness.

Nineteenth century London faced the same challenge. Not until 1886 did more than half of London homes have water supplied 24 hours a day, 7 days a week. The move to a constant water supply reduced mortality. For every 5% increase in the number of households with a constant supply, deaths from water-borne illnesses fell 3%.

During Victoria’s reign, eight water companies supplied the metropolis with water: 50% from the river Thames, 25% from the river Lea and 25% from wells and springs. By the 1860s, the companies filtered all surface water and Bazalgette’s intercepting sewer was under construction. Still, more than 80% of people received water intermittently, storing it in cisterns often located outside the house, uncovered or beside the toilet.

Rapid population and housing growth required the expansion of the water network and companies found it easier to introduce constant service in new neighbourhoods. Retrofitting older neighbourhoods proved challenging and risked a substantial waste of scarce water. The Metropolis Water Act of 1871 finally gave water companies the power to require waste-limiting fixtures. After 1871, new housing estates received a constant supply of water immediately, while old neighbourhoods transitioned slowly.

As constant water supply reached more people, mortality from diarrhoea, dysentery, typhoid and cholera combined fell. With 24-hour supply, water was regularly available for everyone without risk of contamination. Unsurprisingly, poorer, crowded districts had higher mortality from water-borne diseases.

Even though treated, piped water was available to all by the mid-nineteenth century, everyone benefitted from the move to constant service. By the time the Metropolitan Water Board acquired London’s water infrastructure, 95% of houses in the city received their water directly from the mains.

According to Sergio Campus, water and sanitation head at the Inter-American Development Bank, the current challenge in many places is providing a sustainable and constant supply of water. In line with this, the World Bank’s new Water Supply, Sanitation, and Hygiene (WASH) poverty diagnostic has added frequency of delivery as a measure of water quality, in addition to access, water source and treatment.

Regularity of supply varies substantially across locations. London’s experience during the late Victorian years suggest that increased frequency of water supply has the potential to deliver further reductions in mortality in developing countries beyond the initial gains from improved water sources and treatment.