(Bloomberg) -- It’s approaching midnight on a leafy, residential street in southeast London, and Stewart Knowles is listening for water. Bent sideways, with a focused expression, he leans his head on a stick, like a doctor with a giant stethoscope, detecting the telltale wish-washing noise that suggests a pipe is leaking. “I’ve always described it as like a shell when you put it to your ear,” he says.

Knowles manages a team of London water utility workers who solve drippy mysteries in the city's underground pipes and tunnels. His employer, Thames Water, knows how much water should be used by its customers in each area. When too-high amounts are consumed, his team investigates, triangulating the exact location where water is escaping before seeking permission from the council to dig up a road and fix the leak.

A fifth of Britain’s water supply is lost through the kinds of leaks that Knowles is searching for. The problem was easy to overlook when the country — long associated with soggy weather — had consistent and plentiful rainfall. But climate change driven by ever-increasing emissions of greenhouse gases is shifting once-benign weather patterns toward extremes of heavy rain and drought. Wasted water has become a worldwide concern as regions from the US Southwest to Northern Africa experience more unusually hot and dry periods.

By 2050, the UK’s Environment Agency expects the gap between available water and what’s needed by homes and businesses to reach 4 billion liters per day in England — enough to fill 1,600 Olympic size swimming pools. Leaks are part of the picture, but so is a neglected network, some of which was built more than 150 years ago, that doesn’t store enough for times of drought, and water consumption that outstrips many other parts of Europe.

The crisis has become a national obsession. The public is furious with a privatized English water industry that has paid out millions to executives and shareholders while failing to keep pace with population growth and climate pressures, and the government and regulators that have allowed it to happen. As well as the threat of water shortages, underdeveloped pipes and treatment plants mean raw sewage is frequently dumped in rivers and the sea, causing environmental damage.

Now, after years of delays, the UK is racing to fix its broken water system before it’s too late. “The worst risk has not materialized yet,” says Jim Hall, a professor of climate and environmental risk at Oxford University and a member of the government’s official infrastructure adviser. “There is some sense until now that we’ve got away with it,” he says, but “a severe and prolonged drought could materialize at any time.”

Rain is so important in British culture that the rolled-up umbrella was for many years part of the uniform for workers in the City of London. But the UK capital isn’t actually as wet as its reputation suggests. While the western part of the country can have as much as 90 inches (229 centimeters) of rain a year due to damp westerly air from the Atlantic, parts of southeastern England — including London — get less than a quarter of that. Some areas see less rain on average than Beirut, Nairobi or Perth.

Water shortages have become more common during hot periods, when evaporation from reservoirs increases just as demand goes up. Government experts warn that the UK is not prepared for more “extreme climate shocks” such as the punishing summer of heat waves and drought it experienced last year. Forecasts for river flows and groundwater levels up to 2080 by the UK Centre for Ecology & Hydrology suggest that water scarcity is only going to get worse.

This February was the driest in three decades, followed by the wettest March in 40 years. This wouldn’t be a problem if there was enough infrastructure to save all that excess water for a non-rainy day. But no new reservoirs have been built since 1991, despite the population rising by 10 million people since then. Britain still relies on its natural rivers and streams for water, putting pressure on wildlife at times of low flow. There is hardly any capacity for water sharing between areas, no water recycling and little desalination.

Companies have been slow to invest in solutions, choosing instead to keep customers happy with lower bills and return profits to investors. That approach is changing as the extent of the problem becomes clear. Water companies are spending £14 billion on 14 new reservoirs and projects, including pipes to bring water from the west — which tends to get more rain — to the parched east. Along with a planned £10 billion fix for the sewage crisis, that will raise water bills this year, with more increases expected in the future.

“We’ve been through a period of cheap finance, and yet the emphasis from ministers has always been to keep bills low,” says Alastair Chisholm, director of policy at the Chartered Institution of Water and Environmental Management, an industry group. “It’s been a long-term failure to make hay while the sun shines.”

The water troubles are reshaping a central part of British national identity: tending to gardens and fields.

Trees and flowers are more than just pretty frippery in the UK. In 2019, horticulture added £29 billion to gross domestic product and employed more than 670,000 people. A water outage during periods of peak demand could destroy around half of the sector’s businesses, a recent industry survey found.

Chapel Cottage Plants, which supplies cuttings to garden centers and retail stores, saw week-on-week sales slump by as much as 50% in places where water bans were implemented last year. “The public simply were not doing their gardens because of the extreme temperatures,” says Chris Green, a sales manager. “The ground had dried up to the extent that it just wasn’t feasible.”Last year was a “wake-up call,” says Richard Barley, who oversees horticulture at west London’s Kew Gardens, home to the world’s largest collection of living plants.Located in one of the most water-stressed parts of the country, Kew’s lush lawns faded last summer as England turned dry and recorded its highest-ever temperature. Barley and his colleagues now send some species north to an arboretum in rainier, more temperate Yorkshire, and have started planting more Mediterranean and drought-tolerant plants. At the Chelsea Flower Show, a prestigious garden festival in London, multiple exhibitions this year also featured heat-resistant plants and permeable paving.

Barley, an Australian who was previously director of Melbourne’s botanical gardens, has more experience than most British horticulturists with severe heat and drought. “Traditional gardening in the UK has often been about growing a wide range of things, and, where necessary, using a lot of irrigation to keep lawns and garden beds green,” he said. “That’s where we have to think a bit more responsibly about water use.”

Farmers in the UK’s southeast, many of whom have enjoyed plentiful rain and fertile soil for generations, have also been caught off guard by the changing climate. The rolling fields of wheat, sugar beet and rapeseed oil in the country’s southeast, integral to a national push to fill grocery stores with more home-grown produce, are under threat like never before.

Last year’s dry weather led to some crop failures, and in 2020 droughts and heavy rainfall brought wheat yields down by 40%. Andrew Blenkiron, who tends 7,000 acres of farmland in Suffolk, estimates he lost up to 90% of crops in some of his maize and sugar beet fields in 2022. His grandparents raised livestock in Yorkshire’s uplands and rarely had to worry about water supplies. Today, their modern successors have to move their animals around more to ensure they have enough to drink.

This winter he decided to plant fewer potatoes and onions, which suffer in dry conditions. He didn’t sign contracts to supply supermarkets with as much produce as usual this year, resulting in a £100,000 loss, because he’s worried river and reservoir levels won’t recover enough. “We can’t guarantee to be able to see them through the season,” he says. “We’ve already taken a massive hit to our business.”

Still, for many Britons, it hasn’t sunk in that England isn’t as water rich as before.

Each person in the UK consumes, on average, 150 liters of water per day. That’s well above the 120 liters used per person on average across the European Union. The British government wants to cut that number to 110 liters by 2050, but it’s a tough sell. In a 2020 survey, British consumers ranked water saving of low importance — below tackling food and plastic waste and energy consumption.

The government has proposed regulations that will ensure new housing developments build soakaways and tanks to catch greywater so it can be reused. Officials have also pledged to streamline the permitting process so new reservoirs can be built more quickly; many projects have faced local opposition.

But the state has also made clear that it’s relying on water companies to act quickly. “We expect water companies to step up their own efforts to adapt to changing weather patterns and tackle leakage,” water minister Rebecca Pow said in a statement.

This summer — like all going forward — brings new jeopardy. And customers want to see water companies doing their part. The work of leak detectors, however, is mostly done under the cover of darkness. It’s easier to hear drips at night.

On the street in southeast London, the Thames Water workers are warily eyed by locals scurrying home. As lights go out in nearby windows, the team packs up and prepares to find their next broken pipe. Their shift ends when the city wakes up tomorrow. 

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