A hosepipe ban is to be introduced for more than two million people in Sussex and Kent as the country swelters during the current heatwave.
South East Water said it was bringing in the restriction over water shortages in those regions.
Schools have been forced to close during the hot weather and bottled water stations have been set up as the utility firm said demand for drinking water has reached "record levels".
The company said the temporary hosepipe restrictions will come into force from 26 June and means customers cannot water their gardens, wash cars, boats or patios and are banned from filling paddling or swimming pools.
It comes as the NHS warned soaring temperatures, which are forecast to climb into the 30s in some areas, had contributed to one of the "busiest days ever" in A&E departments.
The Met Office has also raised the wildfire risk to 'very high' over much of England and parts of Wales.
South East Water's chief executive David Hinton said:
"This situation has developed much more rapidly than last year.
"Understandably, we've seen customer demand increase in line with the hotter weather, however this has impacted our ability to keep all customers in supply at all times.
"Despite asking for customers' help to use water for essential uses only, regrettably we've now been left with no choice but to introduce this temporary use ban restriction to protect customers' supplies across Kent and Sussex."
He added:
"The long-term forecast for the rest of the summer is for a dry period with little rainfall, although temperatures may reduce slightly.
"Restricting the use of hosepipes and sprinklers to make sure we have enough water for our customers' essential use, will ensure we can serve our vulnerable customers and to protect the local environment."
South West Water already has a hosepipe ban in place with the region still officially in drought.
Restrictions which had been in place for Cornwall and a small part of North Devon since last year were extended in April to other areas to help reservoir levels recover.
(c) Sky News 2023: Millions to be hit by hosepipe ban
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