Severe drought has been declared in parts of southern England after months of dry weather drove some reservoirs to exceptionally low levels.

Most of England and all of Wales were already under drought conditions after both nations’ hottest summers on record, which has taken its toll on rivers, crops and nature.

Roughly 30 million people across parts of England and Wales are covered by hosepipe bans, as part of water companies’ efforts to manage supplies.

So how is your area doing and are you in a drought?

“Severe drought” – the highest category – has now been declared for parts of Cornwall, Devon, Dorset, Somerset, East Sussex and West Sussex.

It means environmental authorities will ramp up monitoring of reservoir levels, river flows and water quality, as well as carry out extra checks on businesses withdrawing water from natural sources.

The “severe drought” classification was introduced following the 2012 drought and this is the first time it has been implemented.

The UK government says two previous events would have met the “severe drought” classification, had it been in place. They are:

Most of England and all of Wales were already in drought, following earlier announcements by the Environment Agency (EA) and Natural Resources Wales.

Parts of north-east and north-west England are in the category below drought, called “prolonged dry weather”.

There are no official droughts currently in Northern Ireland.

There is no single definition of drought, but it is characterised by a period of low rainfall. As the ground dries out, crops and vegetation can begin to struggle.

If dry conditions persist, rivers, reservoirs and groundwater levels can also fall, putting pressure on water supplies.

The EA says that south-east and south-west England have experienced their driest April to September in more than a century.

Scotland does not declare droughts but monitors “water scarcity” – when there is not enough water of sufficient quality to meet demands of people and the environment.

While conditions have improved in parts of Scotland following recent rainfall, some south-eastern areas remain in the most extreme categories of “moderate” or “significant” scarcity, according to the Scottish Environment Protection Agency.

Both drought and water scarcity can lead to hosepipe bans – officially called “temporary use bans” – if they are not already in place.

So far, 11 UK water companies have announced hosepipe bans in 2026. This means hosepipes cannot be used for watering gardens, washing vehicles and windows, and filling pools.

Ten companies are spread across central, southern and eastern parts of England, and one is in Wales.

Our three main sources of water are reservoirs, rivers and from deep underground.

A key reason why parts of southern England have entered “severe drought” is low reservoir levels.

At this time of year, the Environment Agency says it would expect England’s reservoirs to be about three-quarters full, but they are just over half full on average.

Ardingly Reservoir in West Sussex and Wimbleball Reservoir in Somerset are among those at “exceptionally low” levels.

Dŵr Cymru Welsh Water says most reservoir levels in Wales are normal for the time of year.

And reservoir levels in Northern Ireland and Scotland are close to average, according to the latest available data.

Many of the UK’s rivers have also been affected by the low rainfall.

Most monitored river flows in England were classed as “below normal”, “notably low” or “exceptionally low” in July, according to the UK Centre for Ecology & Hydrology (UKCEH).

South-east England relies more heavily on groundwater than reservoirs. Groundwater originates as rainfall and is naturally stored beneath the surface in the pore spaces and fractures in rocks.

Groundwater levels are generally declining following the prolonged dry weather. In September, about half of monitored sites across the UK recorded levels considered “below normal” or lower, with southern England and Wales typically faring worst.

Water can flow more slowly through some rock types than others, sometimes taking years to fully respond to current conditions.

These groundwater stores “respond more slowly to changes in the climate than rivers, which is why they provide a useful buffer during periods of drought”, said Prof Alan MacDonald of the British Geological Survey.

It is why groundwater droughts in the south of England generally take a longer time to develop but can be longer-lasting if they do occur.

Droughts are complex phenomena, driven by a mix of natural and human causes.

The Met Office expects the UK to experience drier summers on average in future as the world warms, though there has been no clear trend so far.

But rising temperatures can play a more direct role by drawing extra moisture from the soil via evaporation.

“A warmer atmosphere is thirstier for moisture and this can mean water in the soil, rivers and reservoirs are depleted more effectively, leading to more rapidly onsetting droughts, heatwaves and wildfires,” said Richard Allan, professor of climate science at the University of Reading.

But there are other factors that determine whether dry conditions lead to water shortages, including how we use water.

In a landmark review into the water sector of England and Wales, water companies were criticised for historic underinvestment in water infrastructure.

And while spring and summer were relatively dry for much of the UK, winter was much wetter than usual, raising questions about how effectively water is being managed.

As part of plans to address water shortages, the government and water companies are planning nine new reservoirs for England by 2050, in addition to one under construction at Havant Thicket in Hampshire.

But the EA has warned that measures to tackle water leaks and control water demand – potentially including hosepipe bans – may be needed in England too.

Water companies in Scotland, Wales and Northern Ireland – which are all public bodies or non-profit – also said they were taking steps to secure future supplies.

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