If you want to understand how Britain got mired in a sewage crisis from which it may never truly escape, the best place to begin is not this year or last year, or for that matter the year England’s water industry was privatised (1989), but more than a century-and-a-half ago.
It might seem odd to begin an account of Britain’s water woes all the way back in 1856, but that, it so happens, was the year of a fateful decision – one that began us on the path we’re still treading today, with growing outrage about repeated sewage outflows into rivers and little progress in resolving it. For it turns out that 1856 was the moment the broad structure of Britain’s (and much of the rest of the world’s) urban water systems were set in stone.
There is much that is complex about the modern water business – the financing of the companies, the regulatory structures that oversee them, the nature of water processing – but actually the real story here is surprisingly simple. It comes back to pipes, or, to be more precise, what goes down the pipes. If you live in a big city like London or Glasgow, when you flush your lavatory the water goes down into the sewer. Same thing for the grey water that comes out of your sink or from the back of your washing machine. But so too – and this is the crucial bit – does rainwater. The rain that comes off your roof or the pavement or the road also flows into the very same drains and down into the very same sewers. This – where rainwater and sewage intermingle – is what is known as a “combined sewage system”.
The biggest problem with a combined system is that every time it rains heavily the system is vulnerable to what are known as combined sewage overflows. The rain essentially overwhelms the sewage system and its pipes, and spills through an outlet into a river or the sea. These spills are supposed to be infrequent, only in the event of very heavy rain but (and it’s hard to overemphasise this) they aren’t a bug in the system – they are the system.
With a combined system like this – in other words with pipes configured the way they are – there really would be no way of preventing 100% of all sewage spills unless you covered much of the country with sewage plants or built tunnels and storage tanks bigger than you could possibly imagine. Either that or you could allow the sewage to flow back into peoples’ homes. That’s the logic of the pipes.
Now, if you were going to design Britain’s sewage system from scratch today this is not, to put it mildly, the design you’d pick. You’d be far more likely to opt for something else – a separate system, where there is one pipe for sewage and an entirely separate pipe for rainwater.
There would still be challenges even with a separate system. For one thing, road water is surprisingly dirty, so allowing it to course straight into rivers is not a good idea. Even so, these days separate systems are seen as the gold standard, because they help safeguard sewage plants from being overwhelmed in the event of a downpour.
But for most of us it’s simply too late. Britain’s main urban areas all have those combined systems which “bake in” sewage spills pretty much forever. And while some in the water business say that since the 1960s all new sewage systems have been of the gold standard “separate” variety, as we’ll see in a moment the reality is considerably more murky.
But here’s the thing. In a parallel universe we might never have had this combined system at all. Sewage overflows might have been a pipe dream.
Which brings us back to that fateful decision in 1856 – a decision taken in the face of what later became known as ‘The Great Stink’.
Victorian London had been struggling with an ever-worsening sewage problem. There had been repeated cholera outbreaks – most notably the epidemic of 1848, which resulted in tens of thousands of deaths. Social reformers like Sir Edwin Chadwick campaigned for change, urging the authorities to clean up the city, but things seemed to be going from bad to worse.
As Stephen Halliday has documented in his definitive study, The Great Stink, the advent of the water closet had the perverse effect of dramatically increasing the amount of liquid going into the primitive sewage systems of the era.
There was no conception of sewage treatment as we’d see it today. In practice, ever-increasing amounts of sewage were being flushed into the Thames and its tributaries. And the more sewage went into the river, the more it stank and, even more importantly, the more people got sick – because most households’ drinking water came from the very same river.
Eventually the authorities convened a series of inquiries, the first of which was led by Chadwick. His vision for London’s sewage system was not dissimilar from that separate system people are still fantasising about today: sewage would go down one pipe while rainwater went down another. Eventually that sewage would be processed and turned into manure, which could be used as a fertiliser.
And so, for a brief period in the mid-19th century there was a tantalising moment when it looked as if London would end up with a separate sewage system. Indeed, Chadwick was hardly the only person advocating it: other engineers came forward with detailed plans to create separate pipes for sewage and others for rainwater. But in the event, the commissioners ended up choosing a different design – the one advocated by Sir Joseph Bazalgette.
Bazalgette was a civil engineer who had been appointed chief engineer to the Metropolitan Board of Works. His solution to the Great Stink, which became so unbearable that in 1858 the Houses of Parliament had to be abandoned, was the sewage system we have today.
London’s home pipes and drains – carrying both sewage and rainwater – would all empty into a series of sewers running along the embankment next to the Thames and taking them east of the city, where the waste would collect before being emptied into the Thames, to flow out in the tide to the North Sea. So was born the sewage systems most of us use today.
And where London led, everyone else followed. Every other major town and city in the country introduced similar combined sewage systems – not to mention many cities and regions in Europe and North America. Bazalgette’s fateful decision, to choose the combined system and ignore the protestations of people like Chadwick, changed the world forever.
Now, Bazalgette’s sewers, and the other public works he helped build, are rightly recognised as extraordinary achievements. By helping channel muck out of the city, they prevented future cholera outbreaks. He and his pipes saved countless lives.
Moreover, they have stood the test of time. London’s sewage still passes through the same brick and concrete tunnels laid down by Bazalgette and his engineers more than a century and a half ago. His system, designed when the city had a population of around two million, is now being used by a population of nearly nine million. It is a marvel.
But it is nonetheless a combined system, designed from the start to discharge sewage into the river in the event of heavy rainfall. And as the population has grown and the square mileage of Britain’s cities expanded, with ever more concrete and asphalt surfaces channelling ever more rain into the drains, those discharges have become more and more frequent.
Back in Bazalgette’s lifetime London’s system was supposed to discharge for around 12 days a year, during the heaviest rain storms. Today there are more than 60 days a year.
And that’s the most important thing you need to know about Britain’s sewage system. The first big problem is, well, the system.