Water companies warn of the likelihood of more shortages due to climate change and lack of investment in infrastructure

Londoners face a one in five probability of queuing in the street at standpipes for their water for days or weeks during a sweltering summer in the coming 25 years, owing to drought brought about by climate change and a lack of water infrastructure, new data suggests.

As the UK basked in unaccustomed September heat, with temperatures topping 30C on Tuesday, a report commissioned by water companies found that the likelihood of droughts was increasing, while investment in water supplies failed to keep up with likely demand.

The threat to London is particularly dire, as the population of the south-east of England is set to increase markedly while steady rainfall declines, and there are few new sites available for the reservoirs that may be needed.



The economic costs of such a drought would amount to as much as £1.3bn a day in the most severe case, according to the report, published on Tuesday by Water UK, the trade association for water utilities.

The report, called Water Resources: Long-term Planning Framework, shows a 20% chance of a drought requiring standpipes in London for periods of several days to weeks occurring in the next 25 years.

Avoiding such a probability would cost an extra £3bn to £5bn, added to customers’ bills on top of inflation and other infrastructure costs, according to Doug Hunt, of the engineering firm Atkins, a co-author of the study, which was commissioned from engineering companies and academics and paid for by water companies.

While the likelihood of future floods has taken up political attention, owing to dire events in recent winters and the millions of people displaced from their houses, with associated costs, the risk of future droughts has been largely overlooked.

Droughts have tended to be more of a problem for farmers than urban residents, for whom hosepipe bans have been the main effect. But the UK’s creaking infrastructure and the increased severity of climate change are likely to mean that Londoners in particular face a future where serious water shortages become more common.

The UK is currently experiencing its hottest September days since 1949. Globally, data just published shows that August and July were the hottest yet on record.

The last major drought warnings for most of the country occurred in 2012, but there have been localised problems and close calls since. Britain’s water and sewage infrastructure were built, from the 19th century, to withstand far different weather circumstances than those that are beginning to prevail as global warming takes hold.

Climate change is likely to mean an increase in extreme weather of all kinds - floods, droughts, heatwaves and fiercer storms - with changes in rainfall patterns having knock-on effects on current infrastructure.

One thing that both droughts and flooding have in common is a lack of storage space for water: in the case of floods, centuries-old storage spaces such as river flood plains and water meadows have been drained or redeveloped for agriculture and housing; and in the case of droughts, few new reservoirs have been built in the areas where they are most needed, particularly in the south-east of England.

Sewage is also a key problem, as sewers can overflow during floods but become backed-up during droughts, when there is not enough water to flush material through the pipes. When rainfall resumes after a period of drought, the resulting back-up can cause blocked sewers and flooding.

Thames Water has been criticised for selling off 25 of its reservoirs in the wake of privatisation, despite the threat of water shortages in London.

Hunt told the Guardian that these reservoirs would have had “no effect” on the utility’s current and future resilience to drought, as they were “service” reservoirs intended to balance the load between supply and changing demand, rather than “storage” reservoirs to collect water.

However, the company is now facing having to buy new - and expensive - land for creating new storage reservoirs around London in order to provide reassurance against shortages, if measures to encourage residents to reduce their water use are insufficiently effective.

Michael Roberts, chief executive of Water UK, the utilities’ trade body, said: “Since privatisation, the industry has invested billions of pounds in securing the nation’s precious water resources, but we all need to do more in the face of current and future pressures on those resources.”

Rose O’Neill, freshwater programme manager at WWF-UK, said that abstraction licences, used mainly water companies and farmers to take water from existing rivers, lakes and underground sources, should come under urgent review.

She said: “Pressure on our rivers and water supplies is only going to rise. We need to act now to ensure we have enough water for people and nature in years to come. [The system of granting and monitoring] abstraction licences is out-of-date, unsustainable and not fit for purpose. It urgently needs reform.”

Simon Gosling, associate professor in climate risk at the University of Nottingham, said the report added to the body of evidence that the UK should expect and increase in the frequency and severity of droughts, owing to climate change. “This, when coupled with projected population growth scenarios, creates an important risk to water infrastructure as a result of water demand exceeding the available supply,” he said.

“One of the recommendations in the report is for a ‘twin track’ approach to future water management, which would involve an enhancement in the supply of water along with improved management of the demand for water. This recommendation confirms one of the conclusions from the UK Climate Change Risk Assessment, published earlier this year, which noted that new policies and increased efforts are needed in order to provide more ambitious reductions in water consumption, and planning of new water supply infrastructure.”

Dr Marc Stutter, a research leader on water management at the James Hutton Institute in Scotland, told the Guardian that the report should help policymakers looking at government actions such as the licensing of businesses that need to use water.

He said: “In terms of the disposal route of effluents to waters these are based on licensing discharge based on a safe level of effluent dilution with river flows. These need to recognise future risks of extreme drought and impaired dilution leading to severe ecological stress. The modelled scenarios [in the report] are a good basis [for further study] to understand drought effects for business sectors and the environment that rely on water.”

Dr Richard Harding, research fellow at the Centre for Ecology and Hydrology, added: “The UK, particularly the south-east, faces a critical water supply situation in the coming decades, with the twin pressures of rising population and the likelihood of increasing drought due to climate change. We mustn’t let the recent run of wet years, since 2012, lull us into a sense of complacency, because the weather patterns could very well switch, as they did in the spring of 2012.”