Thames Water has announced a hosepipe ban across the south of England, which will affect 15 million of its customers.
The ban will come into force from 24 August, affecting people in London and the Thames Valley area.
Using a hosepipe to water gardens or to clean cars will no longer be allowed, except by businesses and farmers.
The temporary ban comes after reports that the source of the Thames had dried up during the drought.
The measure follows a hosepipe ban announced for the first time in 26 years by South West Water, which covers Cornwall and parts of north Devon, and after extremely dry conditions across the UK, with drought having been declared across eight areas of England by the Environment Agency.
Sarah Bentley, the chief executive of Thames Water, said the ban had been a “very difficult decision”, adding: “After months of below-average rainfall and the recent extreme temperatures in July and August, water resources in our region are depleted.
“Customer demand is at unprecedented levels and we now have to move into the next phase of our drought plan to conserve water, mitigate further risk and future-proof supplies.”
Thames Water’s decision to restrict the use of hosepipes follows other measures by the company to conserve its water supply, having said it would fix more than 1,000 leaks across its 20,000-mile network every week.
In a statement on its website, the company said: “After the driest July on record, and below-average rainfall in 10 of the last 12 months, water levels in our rivers and reservoirs are much lower than usual. We have more teams reducing leakage than ever before, working 24/7 to find and fix more than 1,100 leaks every week. The recent heatwaves mean that demand for water is also at record levels.
“We’ve been working around the clock to supply everyone, and customers have been brilliant at saving water where they can. But, with low rainfall forecast for the coming months, we now need to take the next step in our drought plan. Everything we do now will help protect supplies next summer and help the environment.
“We know these restrictions impact your day-to-day activities around your home and beyond, and we’re grateful for your support.”
The hosepipe bans come after the UK recorded its hottest temperature of all time, with the heat soaring above 40C on 19 July.