At the start of 2026, a drought might have seemed unthinkable, after the UK experienced its eighth wettest winter since records began.

But just seven months later, England’s reservoirs are averaging 66 per cent full – far below the 80 per cent usually expected for this time of year, with two Somerset reservoirs, Wimbleball and Clatworthy, now less than half full.

Professor Hannah Cloke, a hydrologist at the University of Reading, said the UK’s water network “does not build years of storage into the system, so one wet winter does not guarantee healthy reservoir levels through a dry year”.

This winter’s rain did top up supplies, she said, but “an exceptionally dry and hot spring and summer” drained them again just as fast.

The government knows this is a problem. In 2025, it promised nine new reservoirs to boost the country’s water storage.

None of them has been built yet – and Cloke says part of the problem is simple “inertia”, with Britain continuing “as normal” even as the climate changes around it.

The plans for new reservoirs

The nine reservoirs are planned across Lincolnshire, Cambridgeshire, Oxfordshire, Somerset, Suffolk, Kent, East Sussex and the West Midlands.

Some are further along than others. The White Horse reservoir, near Abingdon in Oxfordshire, and the Fens reservoir, near Cambridge, are the most advanced, though both remain in the planning and design stage, with White Horse expected to be completed by 2040 and the Fens by 2036.

Costs for White Horse have already climbed sharply – estimates for construction have more than tripled since the project began, and it could now cost bill-payers up to £7.5bn.

Others are much earlier in the process. Mendip Quarries in Somerset cannot begin construction until quarrying ends in 2040. River Adur in Sussex doesn’t even have a confirmed site.

The one reservoir actually under construction right now isn’t part of the nine. Havant Thicket, near Portsmouth, was already under way before the government’s 2025 pledge, and is due to open in 2031 – the first new major reservoir to open in England in more than 30 years, since Carsington Water in Derbyshire.

Why does it take so long to build one?

Building a reservoir is a major undertaking, and it can take anywhere between 15 and 25 years from the first proposal to the taps actually turning on. Four separate hurdles stand in the way.

The first is finding a location. Reservoirs need a lot of space – often several square kilometres – and the right type of soil nearby to supply construction material.

As Terry Fuller, chairman of the Institution of Civil Engineers’ National Reservoir Infrastructure Forum, put it, these sites “don’t grow on trees”.

Getting planning permission is its own hurdle, and one that can take years to clear. One thing that can complicate this stage, according to Fuller, is that the planning authorities at local councils are “famously under-resourced” and often have limited experience when it comes to approving reservoirs.

“It’s a very specialist thing compared to, say, a house extension, for example,” he said.

The government has tried to bypass some of this for its three most advanced projects – White Horse, the Fens and South Lincs – by automatically classing them as “nationally significant infrastructure”, which hands the final planning decision to the government. However, the other six new reservoirs don’t have this status.

Then there’s geography. Much of the South and East of England – where water demand is highest, but rainfall is lowest – is also some of the hardest places to build a reservoir.

Traditionally, reservoirs were built by damming a valley, flooding it to create a lake held in place by walls at one end. That works well in hilly areas like Wales, the Pennines and the Lake District, but most of those sites are already in use.

The South and East of England, by contrast, is largely flat, with no valleys left to dam. Instead, something closer to an artificial lake has to be built, with a ring of embankments made from specialist clay enclosing it on all sides – a significantly more costly endeavour.

The final challenge is filling the reservoir. Rain alone isn’t enough, and many new sites also have no single large river to draw from, relying instead on pumping in surplus water from smaller sources during winter.

The Fens reservoir shows how this issue can derail a project. Its progress through planning was delayed after regulators said developers had not resolved how they would fill it, since the site relies on a mix of smaller rivers and a man-made drainage network rather than one clear source.

A spokesperson for the Department for Environment, Food and Rural Affairs said the Government was “securing water supplies for the future” with £104bn of private investment to fix leaks, build the nine reservoirs and secure supplies, and was “streamlining the planning process” by fast-tracking projects as “nationally significant”.

Why reservoirs might not be enough

Even if all nine reservoirs are built, they won’t solve Britain’s water problem on their own.

The Environment Agency estimates that England alone will need five billion extra litres of water a day by 2055 – far off the 700 million litres the nine new reservoirs are set to deliver.

Much of that pressure is likely to come from Labour’s pledge to build 1.5 million new homes before the next general election, due in 2029.

Dr Megan Klaar, a water scientist at the University of Leeds, said housebuilding “is going to put huge stress” on regions “where they’re already having water restrictions”, like Oxfordshire and Cambridgeshire.

Klaar, and every other expert The i Paper spoke to, agreed that the UK needed to look at other options to ensure water security in the future.

Dr Kevin Grecksch, a water governance expert at the University of Oxford, said water reuse – treating wastewater so it can be used again rather than drawn fresh – was one of “the hottest topics” in academic water management right now.

“Why are we using fresh water to put on our potatoes or on our wheat?” he said, pointing out that around 70 per cent of the world’s fresh water is used for agriculture. “It’s perfectly fine – many countries across the world are already using [treated water on plants].”

He said the technology already exists to treat wastewater to drinking standard if needed – something several EU countries already require by law, and the UK could also look at adopting.

Another option is desalination – removing salt from seawater to make it drinkable – but experts were far less enthusiastic about it. Grecksch compared it to nuclear power in the energy sector: “It all sounds very good on paper, but it comes with some problems.”

It’s highly energy-intensive, he said, leaves behind a “toxic brine” by-product, and costs roughly 10 times more than treating river or reservoir water.

Use less, waste less 

Another option is simply encouraging people to use less water. Klaar said new-build homes should be required to include water-saving devices and water butts – which collect rainwater for gardening – as standard, arguing house builders “aren’t really going to do it on their own volition” without a change in the rules.

She also said water metering – charging households based on how much water they actually use, rather than a fixed rate – could help, since it “makes you realise how much water you’re using” – though she admitted it “wouldn’t be popular.”

But there’s an even “bigger prize” for saving water, according to Cloke – fixing the leaks to tackle the 2.9 billion litres of water lost this way daily. The i Paper revealed last month that water companies were losing far more to leaks than the hosepipe bans they implemented were saving.

Ultimately, most experts agree the biggest risk isn’t any single missing reservoir or unfixed leak, but the danger of standing still.

As Grecksch put it, what’s needed most is “an honest and serious discussion and conversation about the future of our water resources” – something he said has so far been missing amid “a lot of fragmented planning”.