Two water companies were involved with the grand experiment of 1854 in which John Snow studied cholera deaths associated with contaminated drinking water.  During 1845-52, Both companies supplied people living in the same area with polluted water drawn from the River Thames. Then in 1852 the Lambeth Waterworks Company move its water intake to a cleaner location upriver, while the Southwark and Vauxhall Water Company left its intake in the same contaminated location.  

When the next cholera epidemic appeared in 1853-54, some neighbors were unknowingly receiving cleaner water from the Lambeth company while others consumed more polluted water from the Southwark and Vauxhall company.  This change in location of the water intake was the basis for a natural experiment, which allowed Dr. Snow to compare mortality patterns by water source and strengthen his hypothesis regarding the transmission of cholera.   

Grand Experiment

Click here to learn more about the grand experiment of 1854.

Both companies obtained their water from the River Thames.  But where were the intakes located?


John Snow wrote, "The Lambeth Company removed their water works in 1852 from opposite Hungerford Market to Thames Ditton [Seething Wells]; thus obtaining a supply of water quite free from the sewage of London." 

          -Snow, 1855, part 3, page 68. 

There is, however, more to the story.  Since 1785, the Lambeth company had been supplying water to southern and eastern London from an intake on the River Thames near  Hungerford Bridge, in the heart of old London.

At first they used wood mains to transport the water to customers, but then replaced them with iron in the early 1800s.  In 1832, the company constructed a reservoir at Streatham Hill, and then in 1834 constructed new waterworks and a second reservoir in Brixton. Two years later they sold some of their new Brixton site to the city to construct a prison.   All this while, the intake remained in the polluted region of the River Thames. 

In 1847, the Directors of the Lambeth Waterworks Company decided to move the intake from the Hungerford Bridge area to a new location, away from the Thames tides that brought contaminated water to their intake.  They selected Seething Wells next to Thames Ditton, 22 miles up river and far from the contaminated water in the London section of the river. 

The Directors had remembered the cholera epidemic of 1832 and the public outcry over the quality of water.  A pamphlet which Snow published in 1849 brought back these memories, with new thoughts on the cholera hypothesis.  Snow forcefully stated his theory that cholera was caused by "a poison extracted from a diseased body and passed on through the drinking water which had become polluted by sewage."  

More pressure was placed on the River Thames water companies by a report in 1850 by Edwin Chadwick, who recommended that London water should come from new sources, and that private water companies such as Lambeth should be bought out by the government. This was only a recommendation, however, and not law.  Finally in 1852, the Metropolitan Water Act was passed into law, mandating that water companies move their intakes upriver where the water is fresher.  Because the Lambeth company had earlier made the decision to move its intake 22 miles upriver,  they became in 1852 the first water company to comply with the new law. 


In 1845, the Southwark Water Company merged with the Vauxhall Water Company to become the Southwark and Vauxhall Water Company.  


Click here to learn more about the Southwark Water Company before the merger.

Their facility and intake site were next to Battersea Park, upriver a few miles from the Lambeth company intake at Hungerford Bridge.  They had a large ground, with reservoirs covered nearly 18 acres.  While much of their water came from the River Thames, some also was drawn from deep wells. The company used steam engines to force water to a perpendicular height of 175 feet, allowing them to supply much of London south of the Thames. 

The reputation of the new company was awful.  In 1850, the microbiologist Arthur Hassall wrote of the River Thames water they were using,"...a portion of the inhabitants of the metropolis are made to consume, in some form or another, a portion of their own excrement, and moreover, to pay for the privilege." 

The company remained at the River Thames site until 1855 when forced by the 1852 Metropolitan Water Act to move its intake to a location far upriver near Hampton.  At the same time they built four new reservoirs south of the river by Nunhead Cemetery.  Water was then pumped from Hampton to Battersea and on the Nunhead reservoirs.  All this occurred, however, after the period of the grand experiment. 


Maps of Water Companies

Click here to see maps and more on the various locations.



Hardy A. Medical History (Suppl No. 11), 76-93, 1991 

Snow J. On the Mode of Communication of Cholera, 1855.

Weinreb B, Hibbert C. The London Encyclopaedia, 1993.

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