They took the handle off the pump when the cholera was already in retreat

The map, December 1854

578 bars, each one a person

Snow drew the map after the epidemic, for the second edition of his book on cholera; the preface is dated 11 December 1854. Every death is a black bar at the house where the person lived. Here the bars sit on the streets of today's Soho; Broad Street is now Broadwick Street.

Rusty Dodson and Waldo Tobler's digitisation of the map counts 578 bars, fewer than the 616 cases in the table. Some people died in hospital or in other parts of London, and the house they came from was not recorded. Snow marked the deaths “as far as I could ascertain them”.

On foot, by the streets

Two in three of the dead lived nearer the Broad Street pump than any other

In 1854, drinking water came by the bucket from pumps in the street. Snow measured distance the way people walked it, along the streets, and on a second map he drew the line of points equally far from the Broad Street pump and its neighbours.

Redone on today's streets for all 13 public pumps on the map, the calculation gives the same picture: 378 of the 578 dead lived nearer, on foot, to the Broad Street pump. Half of them had at most 148 metres to walk to it.

The pump people avoided

Neighbours disliked their own pump and walked to Broad Street

Another 71 of the dead lived nearer the pump at the end of Carnaby Street, which Snow calls “the pump in Marlborough Street” and Whitehead the Little Marlborough Street pump. Snow found out why that mattered: its water “was so impure that many persons avoided using it”, and those who died near it in early September had water from the Broad Street pump.

Broad Street water was sought after. It was served in coffee-shops at dinner time, mixed with spirits in the public houses, and sold in little shops “with a teaspoonful of effervescing powder in it, under the name of sherbet”. Of 48 people who died in houses nearer other pumps, Snow found that 28 had drunk Broad Street water from preference shortly before falling ill.

The workhouse in Poland Street

535 people in the workhouse, five deaths

The parish workhouse was more than three-quarters surrounded by houses where someone had died. Of its 535 inmates, five died of cholera.

It had its own pump-well, besides water from the Grand Junction company, and “the inmates never sent to Broad Street for water”. Had its death rate matched the streets around it, Snow wrote, upwards of a hundred people would have died.

The brewery

The brewery men did not drink the water

A few steps from the pump, Mr Huggins's brewery employed more than 70 men. None suffered from cholera in a severe form; two were “indisposed, and that not seriously”. They were allowed a ration of malt liquor, and Huggins believed “they do not drink water at all”. The brewery had a deep well of its own.

In the same street, at No. 37, a percussion-cap factory kept two tubs “always supplied with water from the pump in the street” for anyone who wanted a drink. Of its roughly 200 workers, 18 died of cholera.

West End, Hampstead

A widow five kilometres away who drank only Broad Street water

Another doctor, Dr Fraser, pointed Snow to an entry in the weekly return of deaths for 9 September: a woman of 59, the widow of a percussion-cap maker, dead of cholera on 2 September at West End, Hampstead. She “had not been in the neighbourhood of Broad Street, for many months”. But she preferred its water, and a cart that went from Broad Street to West End every day brought her a large bottle of it.

The water was taken on Thursday, 31 August. She drank it that evening and on Friday, fell ill on Friday evening and died on Saturday. A niece on a visit drank it too, went home to “a high and healthy part of Islington”, and died. “There was no cholera at the time” in either place. Snow called the two deaths “perhaps the most conclusive of all”.

Try it

How far was the nearest pump?

Pick any street on the map to see the walk to the nearest public pump of 1854, and the distance to Broad Street. The streets are today's; a few courts of 1854 are gone and a few passages are new, so the distances are approximate.