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In the middle of the night of September 2, 1666, a fire broke out in a bakery located on Pudding Lane, in the old City of London, just a few blocks from the Thames. By the morning, much of the surrounding area had gone up in flames. Over the next four days, the fire spread relentlessly. ‘London in 1666 was a tinderbox, ready to ignite at any time,’ write Cathy Ross and John Clark in their 2008 history of the city. That summer, they observe, had been very dry and the warrens of medieval streets were ‘crowded with timber houses, which often leant far out into the narrow streets, making it easy for flames to jump between buildings’ (Ross & Clark, 112).
By the time it had burned itself out, the Great Fire had destroyed 13,200 houses, eighty-seven churches, the Royal Exchange, and dozens of commercial buildings. While the casualties were modest – fewer than ten people died – the consequences were devastating, with over 100,000 Londoners left homeless. The disaster, moreover, came just a year after an especially lethal plague pandemic, linked to fleas on rats. It killed tens of thousands of people – a fifth of the city’s population – with outbreaks spreading to the towns on London’s periphery.
State authorities provided a small amount of financial relief after the fire, but the back-to-back calamities forced Londoners to figure out how to build back better, to borrow a phrase from our times. The esteemed architect Christopher Wren drew up an ambitious blueprint that anticipated similar post-fire rebuilding schemes developed after fire consumed Chicago in 1871 and Toronto in 1904. While some of Wren’s most famous commissions – e.g., St. Paul’s Cathedral – date back to this period, his reconstruction plan was ultimately rejected by landowners.
In fact, the Great Fire’s most enduring legacy doesn’t involve buildings, but rather the civil engineering systems that serviced them. Over the next century and a half, London became a globally recognized hub for civil engineers and investors, who together invented not only the technical and commercial foundation of modern water and sewage infrastructure, but also the paradigm for the first truly scalable networks – a form that would be replicated in services from gas street lights to rail to modern telecommunications. ‘As these networks proliferated, they changed urban life, rendering it more habitable and less hostile,’ observes Leslie Tomory, a technology historian who describes the emergence of London’s water systems as ‘the roots of the networked city’ (Tomory 2015).
In 1666, London, with a population of about 200,000 people, had no firefighting services and no centralized supply of fresh water. Most Londoners got their water from wells or fountains, although a small number had it delivered directly into their homes via wooden pipes. A handful of private companies supplied the water to affluent subscribers, pumping it from the Thames, as well as canal-fed ponds situated at higher elevations in the suburbs.
As the city rebuilt, a new financial services industry sprang up: companies that offered fire insurance to property owners. To mitigate their own financial risk, these underwriters also operated their own brigades of firefighters, who – in an intriguing precursor to contemporary corporate branding – wore colourful uniforms that associated them with a particular insurer.
The reconstruction of London attracted many new residents, and the population growth spurred demand for water provided directly to homes. By the late seventeenth century, one water supplier – the New River Company, whose shareholders included King James I – emerged as a dominant firm, drawing water from two springs and the River Lea at Islington Hill, north-west of the city, then distributing it through a rapidly growing network of mains to tens of thousands of subscribers, mostly in the West End. Tomory points out that London, at the time, had seen an influx of new wealth, and consequently mounting interest in consumer products as well as luxury goods and services, among them water. Other water firms were also competing for customers, and by the 1720s, most homes had lead pipe hookups, but New River, he writes, was by far the most profitable, ‘its shares become worth tens of thousands of pounds.’
The commercial success of New River soon threatened to backfire because of the company’s chaotic approach to building out its network, explains Tomory. The firm, which still relied primarily on gravitational pressure to send water through its pipe network, couldn’t provide a steady supply for its rapidly growing customer base. To compensate, New River provided subscribers with water according to a schedule, to be stored in basement cisterns. The company, moreover, balanced its loads by installing valves within its pipes – known as ‘turncocks,’ and accessible from apertures embedded in the road surface.
New Company line workers would fan out each day and turn the valves on or off as a means of directing the flow of water to certain districts at specified times. ‘After a few hours the valves would be shut again,’ Tomory writes. ‘The water supply was cycled between the various mains feeding different areas of the city over various days, which meant in practice that houses received water for two or three hours only a few days a week.’
Despite these supply limitations, New River’s directors, as well as those with competing water companies, took care to provide ondemand free water to the fire brigades of the insurance companies that had started signing up customers after the fire. According to historical geographer Carry van Lieshout, the owners of London’s water companies, acutely sensitive to accusations of profiteering, made sure to not only practise this kind of philanthropy but also promote their own civic-mindedness. ‘In a social environment where business fortunes often depended on one’s reputation,’ she observes, ‘the maintenance of their company’s good name was an essential part of being an eighteenth-century man of business’ (van Lieshout 2017).
Yet the rapid growth of post-fire London – and the accelerating demand for piped fresh water – were pressures that couldn’t be resolved just with PR and supply management. In the coming decades, New River and its competitors began to develop and invest in a range of new technologies designed to improve and expand service.
The first step in this long transition involved optimizing their networks – a set of calculation-based operational adjustments that would be entirely recognizable to contemporary systems engineers. For example, New River’s engineers and advisors, Christopher Wren among them, reckoned that the company should divide up its service areas based on elevation, as measured from the Thames, in order to even out the pressure of the flow for all those dwellings receiving water within a given window of time.
To further standardize the way the network functioned, New River’s consultants advised the firm to invest in the installation of secondary and even tertiary pipes so the large-diameter mains that flowed out of its pumping stations and reservoirs could evenly distribute water to smaller and more localized networks, organized by area and street.
New River also began to take steps to ensure that none of the small pipes that flowed into individual houses were connected directly to the water mains. ‘Customers,’ notes Tomory, ‘were not so keen on having this change implemented because being connected to mains meant a much better water supply, since mains produced a higher pressure with regular flow.’
By the first decades of the eighteenth century, New River and London’s other water suppliers were making significant capital investments in new reservoirs, canals, and pumping stations, creating a privately owned network of modern infrastructure that put the booming city well ahead of other major European commercial centres. These firms, however, had little choice: as the population surged and the city expanded outward, the water companies could no longer rely only on springs and heights of land to power their networks. They had to build reservoirs at higher elevations, and thus invest in systems to ‘raise’ the water, initially with horse power or windmills and, later, with new innovations like water towers and the adaptation of steam-engine-driven pumps for these applications.
The earliest steam-engine pumps had been invented in 1698 and were used for removing water from mines. A coal-fired furnace would heat water, producing steam, which was injected into a cylinder fitted with a movable piston. The steam forced the piston to rise, with the motion transferred to an attached pump arm. Using a second injection of cold water, the steam condensed, producing a vacuum in the cylinder and drawing the piston down again. The up-and-down motion cycle produced the pumping action.
In the 1770s, James Watt, a Scottish inventor, designed a much more powerful, energy-efficient version, marketed through Boulton & Watt, an engine manufacturer and foundry based in Birmingham. While the Boulton & Watt steam engine had many industrial and transportation uses, London’s water companies began purchasing them to pump water into their expanding pipe networks. By the end of the eighteenth century, most of the city’s fresh water supply was being moved around with steam-driven pumps, and almost all of the city’s buildings had fresh water hookups. (In response to the recommendations of a royal commission, the whole system, encompassing the networks of nine companies, was consolidated and removed from private ownership in 1903 with the establishment of the Metropolitan Water Board.)
The massive expansion of fresh water service helped stoke the fortunes of a city whose growth was being fuelled by urbanization, industrialization, and the inbound spoils of the British Empire. Little more than a century after the Great Fire, London’s population had hit a million people, and would double again by 1840. Then, as now, burgeoning cities were marked by extremes of wealth and poverty. The palatial mansions and estates of London’s newly affluent mercantile elite coexisted with overcrowded Dickensian slums and debtors’ prisons.
While the provision of fresh water did improve quality of life, a city the size of London produced unimaginable quantities of garbage, sewage, and human waste (a.k.a. night soil), most of which drained into the Thames or leached into wells, triggering outbreaks of highly infectious water-borne diseases like cholera.
Several decades earlier, Alexander Cumming, a Scottish mathematician, had invented a small device that rendered city life somewhat more palatable, but within the confines of private homes. The so-called ‘S-bend’ pipe created a small reservoir of clean water in the drain beneath toilets, sinks, and tubs. It’s raison d’etre couldn’t be more straightforward: the S-configuration prevented smelly methane gas from wafting back into homes and buildings tied to municipal sewer infrastructure. Cumming patented the S-bend in 1775, and his invention ushered in the era of the flush toilets – initially known as Crappers – but their adoption in England was slow, at least initially.3 Nor did flush toilets, or S-bends within them, effectively confront the enormity of London’s sewage problem. Indeed, municipal rules promulgated in the 1840s requiring homes to drain toilets into sewers instead of cesspits vastly exacerbated the crisis.
Early nineteenth-century London, in fact, was focused on three interconnected preoccupations – the plight of the burgeoning ranks of the poor, their potential rebelliousness, and the need to confront infectious diseases through ‘sanitation reform.’ Throughout the 1830s, Edwin Chadwick, a Manchester-born journalist turned social reformer, emerged as an outspoken advocate for changes to the antiquated welfare system, including the introduction of poor houses for the destitute, laws that incentivized able-bodied people to work, and improvements in living conditions at the societal level, particularly those that affected public health. ‘In 1842 Chadwick’s three-volume report “An Inquiry into the Sanitary Condition of the Labouring Population of Great Britain” became a landmark in social history, with its graphic descriptions of how the filth in air, water, soil, and surroundings was a major factor in the spread of disease, especially in urban areas,’ according to one biographical account (‘Sir Edwin Chadwick’ n.d.). He was eventually appointed to head up a new board of health for London.
Though Chadwick wasn’t an engineer, he had strong views on certain civil engineering matters, such as a new approach to building sewers so they wouldn’t collapse. But in terms of sorting out London’s sewer crisis, the heavy lifting fell to the city’s chief municipal engineer, Joseph W. Bazalgette (1819–91), the official tasked with eliminating the Thames’ stench, which was considered, in that period, a source of infection.
Using funds allocated by the national government, Bazalgette embarked on an epic works project: completing a 3,200-kilometre network of underground sewers so they would all flow into five giant drains, to be constructed along the banks of the Thames, called interceptors (Douet 2021). With the assistance of four mammoth steamdriven pumps, the interceptors would shunt waste way downstream, past the tidal low-water mark in the Thames estuary, thus ensuring the sewage couldn’t be swept back into the city at high tide. The interceptors, in turn, were constructed behind stone river walls and capped by embankments that have functioned ever since as some of London’s pre-eminent public spaces.
Though the scheme was unprecedented in scale and ambition, Bazalgette and his task force of civil engineers brought plenty of know-how to the endeavour – perhaps not surprisingly, given the fact that London had been a proving ground for engineers for decades. Many had gained experience with tunnelling and steam-driven pumps while working on railway, canal, or mining projects. This venture, moreover, produced key technical innovations in the use of steamengine pumps, which had never been previously used to move sewage. As industrial archaeologist James Douet relates in his account of the project, Bazalgette’s team invited, screened, and subsequently rejected several proposals from England’s leading steam-engine designers, including firms that built locomotives. But in the process of analyzing the strengths and weaknesses of the various designs, Bazalgette and his engineers teased out a design they considered to be optimal for the task, and then awarded the contract.
It was an exacting and rigorous evaluation process, and one that yielded a new engineering solution that would become standard in the municipal sewage-pumping systems that proliferated in England and elsewhere. Comments Douet: ‘It would have been a surprise had they been other than cautious in planning the world’s first major steam-powered sewage pumping stations in the great national project to which so much discussion had been directed, and on which the future health and well-being of the citizens of the capital depended.’
The powerful sewage pumps were housed in a series of impressive pumping stations, whose ornate architecture expressed the ambition of a transformative works scheme. His achievement altered not just London, but industrializing cities everywhere, including cities like Toronto, whose interceptor sewers date to the 1910s. ‘Bazalgette was an engineer – with no medical background – “of small stature and … somewhat delicate health,”’ adds G. C. Cook in a paper in the Journal of Medical Biography. ‘This man arguably did more for the health of Londoners in the mid-19th century, than anyone before or since’ (Cook 2001). In fact, his legacy as one of London’s pre-eminent city-builders is commemorated at the Crossness sewage pumping station, an extravagantly designed structure that is now a museum.
The long history of toilets and sewers is not only well documented but holds a considerable fascination, the inspiration for numerous books, studies, and websites enumerating the development of this most prosaic but fundamental feature of urban infrastructure.4 However, what’s particularly notable about the evolution of London’s water and sewage systems over a century and a half is that these expanding networks emerged from a confluence of many seemingly disparate forces: the relentless problem-solving ethic of industrial engineers, the enabling role of profit-minded entrepreneurs willing to bet on technological innovation, and the raw political energy ignited by concentrated adversity. It’s worth noting that after years of cholera outbreaks and sewage-filled streets, British parliamentarians finally approved the funding for Bazalgette’s destiny-altering sewer plan because the stench from the Thames, which flows directly beneath the windows of the House of Commons, had become intolerable. Also worth pointing out is that these changes did not emerge from a singular or idealistic vision of some urban future, but rather the serendipitous process of trial and error that informs all innovative processes.
For both fresh water and sewage infrastructure, the balance of the nineteenth century saw more critical engineering innovations layer on top of these existing systems. Emerging scientific insights about the true vectors of microbial infection (Victorians wrongly believed in miasma, or the transmission of illness via bad smells or night air) would be translated into technological and public health advances, such as chlorination, pasteurization, meat handling, and sewage treatment as an alternative to dumping raw human waste into rivers and oceans.
Yet the development and construction of London’s physical infrastructure, by both private and public investors, represented the true turning point. These intricate networks of pipes, drains, sewers, pumping stations, and valves created the baseline conditions under which large numbers of people could survive within dense urban areas. Drawing on engineering and mechanical advances developed for entirely different industrial applications, the water and sewage networks both encouraged urbanization and enabled its acceleration.
London, by 1900, had a population of 6.7 million people – a milestone that simply wouldn’t have been possible without these two foundational forms of municipal infrastructure. The resulting concentration, of course, gave rise to the modern city, with all its social, cultural, and economic dynamism, as well as its distinctively urban politics, hardships, and opportunities.
The invention of the scalable network, moreover, provided a formula for expansion, meaning that cities could grow outward, and beyond their pre-industrial geographical constraints. Those insights, as Tomory argues, also laid the groundwork for other families of urban innovations, including those that would reveal and then illuminate the spaces of cities in an entirely new light.
3. Flush toilets remain a work in progress. ‘More than 170 years later,’ noted a report by the BBC in 2017, ‘about two-thirds of the world’s people have access to what’s called “improved sanitation,” according to the World Health Organization, up from about a quarter in 1980 … But that still means two and a half billion people don't have access to it, and “improved sanitation” itself is a relatively low bar’ (Harford 2017).
4. Among the most comprehensive is a site called Sewer History, maintained by the historian of the Arizona Water Association (Schladweiler et al.).