The Drought Didn’t End When Summer Did

Autumn rain has something psychologically reassuring about it.

The lawn begins to recover. The garden stops looking quite so exhausted. Puddles reappear. The umbrella migrates back towards the front door and, after a summer dominated by drought, heatwaves, hosepipe bans and wildfires, Britain starts to look reassuringly wet again.

It is tempting to think the drought has ended.

Except it hasn’t.

At the beginning of October, ten Environment Agency areas in England remained officially in drought, with every other area classed as being in prolonged dry weather. National reservoir storage had fallen to just 55 per cent.

At this time of year, it would normally be around 74 per cent.

Sixteen reservoirs or reservoir groups were less than half full. Ardingly Reservoir in West Sussex was at just 23 per cent capacity at the end of September. Wimbleball in Somerset was even lower, at 21 per cent.

Summer may have ended.

Its water deficit has not.

Britain’s water system has a memory

One problem with how we talk about drought is that we tend to associate it with weather.

No rain equals drought. Rain equals no drought.

Our water system is considerably more complicated.

A drought is not simply a period when it hasn’t rained. It happens when a prolonged rainfall shortage works its way through the landscape.

Soils dry.

River flows fall.

Reservoirs decline.

Groundwater levels recede.

Wetlands and habitats come under pressure.

Eventually, if the deficit becomes severe enough, the amount of water available for homes, agriculture, industry and the environment becomes constrained.

And reversing that process takes time.

England actually experienced its wettest week since early February at the end of August. Rivers responded. Soil moisture improved. Some environmental conditions improved.

Yet reservoir storage still fell.

That sounds contradictory until we understand what happens to rain after it hits the ground.

Where does the autumn rain actually go?

Imagine heavy rain falling tonight.

Some runs rapidly from roofs, roads and other hard surfaces into drains and rivers. If enough falls quickly enough, those rivers may rise sharply and we can even experience local flooding.

Some rain lands on vegetation and evaporates again.

Some soaks into the soil.

Only after soils become sufficiently wet can larger amounts of water move deeper through the ground, replenishing groundwater and eventually adding to the springs and rivers that depend upon it.

Reservoirs have their own catchments and operating characteristics. They don’t simply fill because it rained somewhere nearby.

That means a spectacular thunderstorm can flood roads, overflow drains, and rapidly raise rivers without doing much to restore the strategic water reserves we will depend on next summer.

The rain we really need may be much less dramatic.

Days and weeks of persistent autumn and winter rainfall can gradually wet the soil, increase river flows, replenish reservoirs and allow water to percolate down into aquifers.

In water-resource terms, a grey, damp November can be considerably more useful than an exciting August thunderstorm.

The first job is paying back the deficit

This is what makes autumn 2026 so important.

England isn’t entering the traditional recharge season from a normal starting point.

It is entering it with a substantial deficit.

September didn’t provide the recovery we might have hoped for. England received only around 65 per cent of its long-term average rainfall during the month.

River flows declined at nearly two-thirds of the sites monitored by the Environment Agency during the final reporting week. Almost all were below normal or lower for the time of year. Groundwater continued its seasonal decline.

And despite cooler weather reducing demand, reservoir storage fell at almost all monitored reservoirs and reservoir groups.

The first rainfall of autumn therefore isn’t necessarily building resilience for next summer.

Some of it is simply paying back what we lost during this one.

That distinction matters.

If the winter recharge season is strong, the system can recover. If it isn’t, 2027 could begin with water resources already under pressure.

Groundwater moves to a different clock

Groundwater makes this even more interesting.

Reservoirs are visible. We can photograph the exposed banks and compare today’s waterline with the marks left behind when they were full.

Groundwater is largely invisible.

Yet aquifers are enormously important to Britain’s water supply, particularly across parts of southern and eastern England.

They also don’t necessarily respond immediately to rainfall.

Water must first infiltrate the ground and move through layers of soil and rock. Different geology responds at different speeds. Some aquifers react relatively quickly; others can take considerably longer.

That creates a lag between the weather we experience at the surface and what is happening to the water stored beneath our feet.

The Environment Agency’s projections already suggest that by the end of March 2027, groundwater levels in eastern, south-eastern and north-eastern England have the highest chance of staying below normal or lower.

So we could be standing in the rain this winter while parts of the country’s underground water reserves are still recovering from the summer before.

Why flooding doesn’t mean the drought is over

This also explains one of the strangest features of Britain’s changing water challenge.

We can have a flood during a drought.

It isn’t a contradiction.

After prolonged dry weather, an intense storm can dump a large quantity of water onto one catchment in a matter of hours. Rivers rise, drainage systems weaken and streets flood.

But much of that water can move rapidly through the system and out towards the sea.

Meanwhile, reservoirs elsewhere remain depleted and groundwater levels continue to be low.

It is one reason why WaterMatters has repeatedly argued that Britain’s challenge isn’t simply having too little water or too much water.

It is increasingly about when the water arrives, where it arrives and what we do with it when it gets here.

We have built landscapes very good at moving water away.

During heavy rainfall, that protects homes and infrastructure. But at the catchment scale, an increasingly important question is whether we can slow more water down, allow more of it to infiltrate into the landscape, restore wetlands, use sustainable drainage, capture rainfall from buildings, and store more water for later use.

The objective isn’t to stop water flowing.

It is to manage its journey better.

Winter is when next summer begins

We tend to think about water shortages when it is hot.

Hosepipe bans arrive. Lawns turn brown. Reservoir photographs appear in newspapers and suddenly everyone starts talking about drought.

But the resilience of our water supplies during July and August is partly determined months earlier.

Winter is when reservoirs traditionally refill.

It is when soils are wetter, evaporation is lower and vegetation uses less water. Rainfall has its best chance to work through catchments and replenish groundwater.

That makes the coming months extraordinarily important.

The Environment Agency says further significant rainfall is needed to return many water companies to normal water-resource conditions.

This matters beyond the public water supply. Farmers are also concerned about whether their own reservoirs will refill sufficiently during winter. Some agricultural storage was reported at only 0 to 20 per cent capacity in September.

We are therefore not simply waiting for rain.

We need the right sort of rain, in sufficient quantities, over a sufficiently long period, in the right places.

British weather has rarely been so cooperative.

The drought didn’t end when summer did

None of this means England is destined to enter another drought next summer.

A wet autumn and winter may transform the picture.

Reservoirs can recover. Rivers can rise. Aquifers can recharge. The landscape can move from deficit towards something approaching normality.

But we shouldn't assume that a few rainy weekends have solved the problem.

That is perhaps the more important lesson from 2026.

Water resilience isn’t something we can switch on when the temperature reaches 30°C.

It depends upon what happens throughout the year: how much rain falls, how we manage catchments, how much water we store, how much we lose through leakage, how efficiently we use it and how successfully we keep water within the landscape rather than simply moving it downstream.

We could develop a useful habit this autumn.

When the rain is battering against the window and somebody inevitably remarks that Britain can’t possibly have a water shortage because “look at all that rain”, don’t look at the puddle outside.

Think about the soil beneath it.

Think about the river beyond it.

Think about the reservoir upstream.

And think about the aquifer slowly replenishing someplace beneath your feet.

Because the most important question for Britain’s water supplies isn’t whether it rains tomorrow.

It is how much of this winter’s rain we still have when summer comes back.