This Is What Will Happen When London Runs Out of Water

This summer, Cape Town will become the first major urban centre to run out of water. If that happens to London, here's what to expect.

Colin Drury

A very dry-looking London. Photo: Stephen Chung / Alamy Stock Photo

When asked last month what risks he was preparing for, Greg Pillay – head of disaster operations in Cape Town, South Africa – pulled no punches. "Water shortages, sanitation failures, disease outbreaks," he told the world’s media. "And anarchy."

His city is on the cusp of a much unwanted claim to fame: it will, this summer, become the world’s first ever major urban centre to run out of water. Three years of record low rainfall and political mismanagement means reservoir levels have plummeted to 13 percent capacity. Day Zero – the apocalyptic moment when the taps have to be switched off – is predicted for July.

If you're reading this in rain-lashed Britain, thinking it's a distant crisis for a distant land, it seems you're mistaken. Both water companies and emergency planners in the UK have long considered a Day Zero-style event a serious enough prospect to routinely plan out what would happen if it occurred. "A range of scenarios are regularly war-gamed to ensure all parties are aware of roles and responsibilities in any unlikely event," Miles Evans, Thames Water spokesman, tells me.

So, how exactly might this arise? Just what would happen if the taps did have to be switched off in a British city? And could we really see disease, anarchy and neighbourhood portaloos in our streets? "You’d like to think not," says Dr Lucy Easthope, a disaster response specialist with the Cabinet Office's Emergency Planning College. "But the thing disaster planning teaches you is that worst case scenarios do happen, and they happen fast."

1. The supply goes down

The UK is self-evidently a country with water: a land of rain surrounded by sea. As a nation, our go-to small-talk is about how it's pissing down outside – or expressing surprise that, for once, it isn’t. Summer here, noted King George II, is two fine days and a thunder storm.

Except, strictly speaking, it’s still not wet enough.

Population growth and climate change means demand for water is increasing just as supply is diminishing. In 2012, there was such concern that a hot summer could leave London facing shortages during the Olympics that a desalination plant was built in Beckton so salt water from the Thames Estuary could be purified in an emergency.

"Just three years of low rainfall would leave most British cities facing serious shortages," says Nick Walton, lead hydrogeochemist with The Institution of Environmental Sciences.

More pertinently, perhaps, it’s not just drought that could switch our taps off. Pipes damaged by freezing weather meant running water was stopped across Merseyside for more than a week in 1963, while this week thousands have been left with no water as a result of frozen pipes being damaged as they thawed out. Water companies are also a known target of terrorists seeking to destroy or poison supplies.

"People look out the window and it's chucking it down, and they don't equate that with lack of water," says Dr Easthope. "But we ignore the risk at our peril."

London looking hot as hell. Photo: Guy Corbishley / Alamy Stock Photo

2. The bans begin…

Unless there is what emergency planners call a "no-notice-big-bang" scenario (almost certainly, in this country, a terrorist attack), a water shortage won’t come out of nowhere. There will be warnings. Some minister will be skewered for incompetence on Radio 4 long before the taps give only fresh air.

At this lead-in stage, people will be asked to reduce consumption. A Temporary Use Ban would limit household rights. Washing cars and filling paddling pools would result in fines. A Local Resilience Forum will coordinate campaigns urging people to flush less and take showers instead of baths.

None of which is unchartered territory. Such bans have been intermittently used for decades, most famously during the scorching summer of 1976: "It became patriotic to have a dirty car," remembered the journalist Ian Herbert 30 years later.

3. Tankers on the roads, standpipes in the streets

For six weeks in 1995, some 1,000 tankers rolled across Yorkshire every single day in the biggest ever peace time mobilisation of lorries. Each carried water from the east of the county – which was flush – to reservoirs in the west, which was facing perhaps the severest localised shortage in modern British history.

The conveys were an unremitting environmental and economic disaster. But they did – just – keep the taps on.

Something similar would probably happen today, reckons Dr Easthope. "But using tankers to redistribute water like this – just like distributing bottled water to homes – is logistically unsustainable; it can't be kept going indefinitely."

What follows afterwards would be unpopular: a limiting of household tap water – perhaps a day with, followed by a day without – and the installing of standpipes and bowsers in the streets. Around this point, COBRA, the government’s highest-level emergency response committee, would be activated. Phrases like "national crisis" would start to get thrown around.

4. The dash for drink

If water supplies are disappearing without being replenished, limiting use of what’s left is no more than a delaying tactic. So, at some point, there will be a dash to find more.

Special licences would be granted to water companies – under and Emergency Drought Order – allowing them to rip up land and property while digging boreholes to access the UK’s huge underground water reserves, called aquafers. In coastal towns, desalination plants may be built to purify sea water for domestic use. In 1976, there was even a plan to seed clouds with rain-bursting chemicals.

Yet, none of these guarantee success.

Boreholes cost £500,000 a pop and could take a year from ground-breaking to connection to the water supply. For a city the size of London, dozens would be needed to even begin to meet demand. Pertinently, says Nick Walton, "The environmental damage of taking water from the earth in such quantity would be incalculable." Think rivers drying up, land turning arid and habitats being destroyed.

Desalination plants, on the other hand, could probably help make up water shortfalls – as long as said shortfalls were confined to coastal or estuary towns. The effectiveness of sucking rain from the clouds, meanwhile, remains unproven.

Photo: Jake Lewis

5. The New Three-Day Week (but full pub opening hours)

Much gaming out around a British city water shortage looks at how the 1973 Fuel Crisis played out.

Not an obvious comparison, perhaps, but during that – as during a drought – suddenly limited resources needed to be maintained and managed. "So, with our water crisis, you may see businesses limited – or self-limiting themselves – to a new Three-Day Week," says Dr Easthope.

Restaurants would be shut on hygiene grounds. Schools would close. Farms would likely see entire crop yields ruined; in 1976, some £500 million worth were lost in Dorset alone. An economic slowdown would be inevitable.

Not everywhere would see reduced hours, though. Certain red-stickered organisations would have water supplies maintained so they could continue as normal – the emergency services, public transport, utilities and care homes among them. And pubs too, apparently.

"Keeping the pubs open is something I fiercely advocate," says Dr Easthope, whose book The Recovery Myth sets out the best way for strategists to respond to emergencies. "They are one of the vital casual spaces of disaster recovery; places where people can go and talk and laugh together. Where they can be normal again."

6. Troops. Fire. Evacuation. Portaloos.

When defence analysts game out wars between major powers, they might end with nuclear Armageddon. When emergency planners game out water shortages, there are community portaloos haunting the final stages.

At some point, household taps would be completely shut off and people would be advised that instead of using their own un-flushable lavatories they should visit newly-installed neighbourhood portaloos. Or build their own compost toilets.

The resulting breakdown in hygiene would see hospitals inundated. Children and vulnerable people may be evacuated to coastal towns. Government-incentivised holiday schemes would encourage families to leave the area for a period. Troops would probably be placed on the streets to protect empty homes and standpipes.

From here, there's really not a great deal to be done other than – assuming the scenario has been caused by a drought – hope the rain comes soon.

And it probably will.

In a recent study, Water UK found there was a 5 percent chance of an unprecedented drought here in the next 25 years. But, as Nick Walton says: "This is England – any period of good weather always ends with a storm."

So next time you’re making small talk about the rain, maybe offer a silent thanks.