Where Did It All Go Before Sewers? Into a Hole, and Eventually Into the Well

A pit was dug near or under a building, lined with stone, brick or timber or left unlined, and covered with a seat or a hatch. Waste accumulated in it and liquid seeped away through the sides and base, which was the point, since only the solids needed removing. When it filled, a contractor emptied it by hand at night, carted the contents out of the city and sold them to farmers as fertiliser, which made the trade genuinely profitable for a long period. Householders paid for emptying, which created an obvious incentive to delay it.

Population density defeated the arrangement in several ways at once:

• •Pits were placed close to wells in crowded ground
• •Seepage carried contamination through the soil between them
• •Emptying was expensive, so pits overflowed into cellars and streets
• •Flush lavatories from the 1850s multiplied the liquid enormously
• •That liquid overwhelmed pits designed for solids
• •Farmers stopped buying, once cheap imported fertiliser arrived

The connection between these pits and disease was established in one of the founding investigations of epidemiology. John Snow mapped cholera deaths in Soho in 1854 and traced them to a single water pump, and although the pump handle removal is the famous part, the decisive finding came later when the pump well was excavated and found to be contaminated by seepage from a cesspit a few feet away, into which a nappy from an infected infant had been washed. That physical link between a pit and a well, established by digging, is what converted an association on a map into a demonstrated mechanism, against a medical establishment that attributed the disease to bad air.

The work of removing the contents supported a recognised occupation with its own guild, rules and reputation. Night soil men in London, and their equivalents across Europe and Asia, worked after dark under regulations specifying hours, and the job paid well because nobody else would do it and because the contents had value. In Edo and later Tokyo the trade was organised on a large scale, with rights to a household's waste bought and sold and the material graded by quality, since diet affected its value as fertiliser. The arrival of cheap imported fertiliser and of sewers removed the income and left only the cost, which is when the arrangement collapsed.

These pits are among the most informative features on an urban excavation, which is an irony worth appreciating. The contents are waterlogged and oxygen-free, so organic material survives that decays everywhere else, including leather, textile, wood, seeds, fruit stones, fish bones and insect remains. That gives a direct record of what a household ate, in what season, and how varied their diet was, which no document supplies. Parasite eggs in the deposits record what the occupants were infected with. Broken pottery, lost objects and discarded rubbish date the layers. Pits from adjacent properties can be compared to show differences in wealth street by street.

A lined or unlined pit held solids while liquid seeped away, and contractors emptied it at night and sold the contents to farmers, which worked until density placed pits beside wells and flush lavatories added far more liquid than the pits could take. Excavating the well beside the Broad Street pump in 1854 demonstrated the physical link to cholera. The waterlogged contents preserve diet and parasites in extraordinary detail.