The ban means Thames Water customers will not be able to use hosepipes to water gardens, wash cars and windows, or fill paddling pools. The company estimated that its Temporary Use Ban will help save up to 10% of water.

The water company said July 2022 has been the driest July since 1885, with the hottest temperatures on record, and the River Thames reaching its lowest level since 2005. These factors have led to a drop in reservoir levels in the Thames Valley and London.

Thames Water said its “robust” drought plan is designed to mitigate the risk of further impact to water resources and “ensure the taps keep running for customers’ essential use”.

It said the recent heatwave and extreme temperatures have resulted in the highest water demand for more than 25 years with the company supplying 2.9 billion litres of water a day to customers across the region. It said that in some areas during the particularly hot weather, demand for water rose by 50% compared to the norm for the time of year.

Groundwater levels are currently below normal throughout the region and declining towards levels that would be only be expected once a decade. Reservoir storage levels in London and Farmoor, in Oxfordshire, have reduced significantly and are now at levels not seen for about 30 years.

While the ban doesn’t cover businesses, Thames Water is asking businesses across its area to be “mindful of the drought and to use water wisely”, for example, by not washing commercial vehicles or turning off water features on their properties.

Sarah Bentley, Thames Water CEO, said: “Implementing a Temporary Use Ban for our customers has been a very difficult decision to make and one which we have not taken lightly.

“After months of below average rainfall and the recent extreme temperatures in July and August, water resources in our region are depleted. Despite investing in the largest leakage reduction programme in the UK, 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 futureproof supplies.”

Thames Water has faced a barrage of criticism for its record on leakages. More than 600 million litres of water is currently lost a week by the company, mainly due to ageing pipes. It has the worst record on leaks out of all nine water companies in the UK.

The company said it is fixing more than 1,100 leaks on its 20,000-mile network every week and has met its leakage reduction targets for the past three years.

Yorkshire Water is introducing a hosepipe ban from 26 August while South East Water has banned using hosepipes since 12 August.