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First water-traps


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(Picture: Patent, courtesy of British Library)


Though primitive flushing water closets had been installed in affluent houses over previous decades, Cumming was granted the first British patent for a water closet in 1775. His design included big improvements on earlier models – most importantly, masking the smell.


Cumming’s water closet was a great leap forward in toilet technology – particularly his introduction of the S-trap, now commonly known as a U-bend. Earlier models had incorporated into the soil pipe a D-trap made from soldered lead, easily manufactured by plumbers. But water in a D-trap tended to sit for long periods, quickly becoming stagnant and foetid, and faecal matter became stuck in its sharp angles.

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Cumming’s S-trap – a double kink in the soil pipe – held a constant amount of water that was completely replaced on each flush. This created an odour-impermeable water seal that blocked smells and sewer gases from reaching the user above.


Another innovation by Cumming (pictured here) was the addition at the bottom of the pan of a metal plate or valve, which held a pool of clean water. Pulling a handle slid aside this plate and, at the same time, released water through a slit low down in the bowl to create a cleansing swirl and to flush away the waste.

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(Picture: The History Collection/Alamy)

There were problems with Cumming’s design. It required a plentiful supply of water, typically filling a cistern above the toilet to feed the flush. Because the metal valve slid aside during the flush, it wasn’t cleaned by the flowing water and, over time, became clogged with filth and prone to rust. In very cold weather, the sliding valve might freeze shut or open – and because many water closets were installed outside, this was a fairly common occurrence. Similarly, the inlet ‘cock’ or valve for the flush water was near the pan, and also liable to freeze.


Of course, there also remained the question of where the waste was taken after it went round the U-bend. The limited sewerage systems of late-18th-century Britain were not intended to carry human waste, so toilet effluent still generally flowed into a cesspit.

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