Joseph Bazalgette: how the man who transformed London paved the way for your loo

Why did London need new sewers?

In 1810, some 200,000 cesspits served London’s more than one million inhabitants – a population that doubled over the following four decades. Because emptying cesspits was expensive and unpleasant, they were often designed to leak liquids into the earth or allowed to overflow into houses and streets.

Indeed, on 20 October 1660 diarist Samuel Pepys wrote that “going down my cellar to look, I put my foot into a great heap of turds, by which I find that Mr Turner's house of office is full and comes into my cellar”.

Waste also emptied into rivers such as the Fleet that, by the mid-19th century, had been covered over to act as sewers flowing into the Thames. Unsurprisingly, the city was prone to awful smells and diseases caused by contaminated water.

• Read more: Tales of the toilet: a historical A–Z

Why and how did Bazalgette act?

Concerns about London’s water supply and drainage grew during the first half of the 19th century, particularly following the arrival of cholera in 1831. That first outbreak killed 6,536 people in the capital; a second, in 1848–49, took the lives of more than 14,000 Londoners. At that time, before scientists established that such water-borne diseases were caused by bacteria, it was widely believed that cholera was a product of ‘miasma’ – bad air. And the air around the Thames had become very bad indeed.

The Metropolitan Commission of Sewers, initiated in 1848, considered dozens of proposed plans to address the drainage problem, but none was authorised. Then, in June 1858, the weather in London turned unusually hot, the level of the Thames fell, and waste piled up on the banks, creating an unbearably foul smell. In the newly constructed Palace of Westminster, MPs assailed by the ‘Great Stink’ could hardly stand the stench. Within weeks, parliament approved funding to enable Bazalgette to begin work.

What was his idea?

Bazalgette’s system involved the construction of 1,100 miles of brick-lined street sewers feeding into 82 miles of intercepting sewers. These were designed to run roughly parallel to the Thames, diverting the waste eastwards to be discharged into the river 12 miles downstream from the city. Building the system proved a long, complex process costing some £4.2m – a vast sum worth more than £500m today. But by 1875 the six intercepting sewers were completed, along with the Victoria, Chelsea and Albert Embankments, beneath which ran underground railway lines, gas pipelines and, of course, sewers. Also constructed were the great pumping stations at Abbey Mills on the north bank, releasing sewage into the Thames at Beckton, and Crossness, the magnificent ‘industrial cathedral’ at the southern outfall on the Erith Marshes.

Bazalgette’s system involved the construction of 1,100 miles of brick-lined street sewers feeding into 82 miles of intercepting sewers

Bazalgette was knighted in 1874, retired in 1889, and died just two years later; his remains lie in a magnificent mausoleum at St Mary’s Church, steps from his home in Wimbledon.

What impacts did Bazalgette’s system have?

London’s riverside landscape was transformed – and so was the health of its population. Cholera and typhoid outbreaks were effectively eradicated, and many thousands of lives saved over subsequent decades. Though the new sewer network greatly improved sanitation, the dangers of discharging untreated sewage into the Thames were exposed on 3 September 1878 when the crowded pleasure boat SS Princess Alice collided with a collier ship and sank downstream from the northern outfall. More than 600 passengers died; of the 130 survivors pulled from the Thames, at least 16 later perished, having ingested the foul water. As a result of the subsequent public inquiry into the incident, from 1888 solid waste was separated from the sewage, and transported downstream on ‘sludge’ boats to be dumped out at sea.

Read more: Tales of the toilet: a historical A–Z

When was the first toilet invented? What are the origins of the term 'crapper'? 

What do his achievements have to do with my toilet?

The earliest flushing water closets were devised long before Bazalgette was born. The first-known example was designed around 1596 by Sir John Harington, godson of Elizabeth I, but it wasn’t until the introduction of odour-blocking water-traps and valves in the late 18th century that flushing toilets began to make headway. The installation by sanitary pioneer George Jennings of ‘spend a penny’ public conveniences at the Great Exhibition of 1851, and his subsequent one-piece ‘monkey closet’, marked the start of a surge in new toilets – designs made possible by the creation of sewers.

The addition of a flush hugely increases the volume of waste produced, so the widespread introduction of flushing toilets became viable only with the installation of comprehensive sewer systems in London and elsewhere. Without the work of pioneers such as Bazalgette, your home wouldn’t have its clean and comfortable flushing inside loo.

Learn more about Bazalgette’s story, and admire the magnificent pumping station he built, at Crossness in southeast London. And to discover his place in the 5,000-year-history of loos, visit the new Toilet Timeline