Around 16 million people could see their areas move into drought status this week as Britain looks set to experience its sixth heatwave of a record-breaking summer.

More restrictions on homes, including further hosepipe bans, are likely to follow, and one water firm is preparing a virtual ban on water use by businesses such as car washes and private swimming pools for the first time in two decades.

Temperatures as high as 35°C are forecast for the middle of this week and look certain to break a heatwave record set in 1995, where the UK saw 34 days of temperatures higher than 30°C. The record was equalled on Sunday when thermometers hit 31°C in parts of southern England.

The soaring heat and prolonged dry spells are putting increased pressure on Britain’s dwindling water supplies.

No rain is forecast in any of these areas in the coming week and the Environment Agency (EA) has said several areas are expected to change their drought status within the next seven days.

Reservoir storage across England has fallen to 69 per cent – 12 per cent below the long-term average for this time of year.

Five reservoirs are now classed as being exceptionally low, with Wimbleball and Blagdon in Somerset now at just 50 per cent and 54 per cent respectively, while Hanningfield in Essex is at 60 per cent.

Businesses face water bans

More than 25 million households are currently under restrictions on water usage in the form of hosepipe bans.

On Friday, South West Water became the latest to introduce restrictions on customers across Devon, Cornwall, parts of Dorset and Somerset and the Isles of Scilly.

Southern Water has applied to the Government to be allowed to issue a Non-Essential Use Ban in Hampshire and the Isle of Wight. This would see businesses banned from activities such as washing cars and windows with hosepipes or other mechanical devices, and filling swimming pools.

The ban on maintaining swimming pools would not apply to facilities open to the public, but would apply to areas that could only be accessed with a membership, for example a gym.

Such restrictions generally do not trigger any right to compensation for businesses.

Southern Water said the application remained a “precautionary measure”, but if it were granted it would be the first time the Government has authorised such a measure since 2006.

Further restrictions are being placed on farmers, who hold licences that typically allow them to abstract water from rivers iso that they can irrigate crops.

More than 1,500 limits of these abstraction licenses are already in place, with more being introduced across East Anglia this week.

Andrew Blenkiron, a farmer in Suffolk, told The i Paper his barley crop, which is used to make beer and whiskey, was down 70 per cent of his expected yields.

He has just built a third reservoir on his farm at a cost of £3m, and this has proved to be an essential investment as one of the three reservoirs is now empty and the other two are down to 15 per cent of their storage capacity.

“We’ve spent an absolute fortune irrigating these crops,” he said. “We probably put almost 80 per cent more water on than we did last year.”

Mass fish kills

River levels are declining across the country, causing environmental problems such as mass fish kills.

The situation could become worse for rivers as water companies seek alterations to their licences that allow them to take more water from the environment during times of drought.

Southern Water has applied for a drought order that would allow it to abstract more than typically allowed from the River Test.

Fifteen Labour MPs have written to the Government asking for leniency on environmental rules during the drought to help farmers.

Low water levels are incredibly damaging to wildlife and can make rivers more vulnerable to pollution. Thousands of dead fish washed up on the banks of the River Wensum in the middle of Norwich last weekend, where water levels have been exceptionally low.

The EA has recorded 134 drought-related environmental incidents so far this year, including fish kills and toxic algal blooms.

Heat health warnings

According to the Met Office, there have already been three widespread heatwaves in the UK so far this year, in addition to two smaller and more localised ones in July.

Yellow heat health warnings have already been issued across most of England, sounding an alert that the extreme heat is likely to affect the wellbeing of the population and put additional pressure on healthcare services.

The alert – for the East Midlands, West Midlands, South East, South West, East of England, Yorkshire and the Humber, and London – will last until at least 9pm on Tuesday.

Two record-breaking heatwaves in May and June led to more than 2,800 excess deaths, and two more heatwaves in July have fuelled drought and wildfires.

The National Drought Group – which includes ministers, regulators, the Met Office, water companies and the National Farmers Union – will next meet on 18 August.