Supplies have been restored after a large burst main forced some schools to shut and left thousands of people without water, Thames Water said.
The company said on Monday afternoon that its engineers had isolated the broken pipe in West Molesey, Surrey, and were working on a permanent repair.
Thames Water said up to 15,000 properties were initially affected by the issue, later adding the number had fallen to 6,000.
Customers in the following postcodes were impacted: CR4, KT1, KT10, KT12, KT2, KT3, KT5, KT6, KT7, KT8, SM4, SW16, SW17, SW18, SW19, SW20, TW10 and TW16.
Meanwhile, some schools and nurseries said they had been forced to shut because of the fault.
Esher Sixth Form College, in Thames Ditton, Surrey, said on its website: “Due to a major water outage affecting the KT10 area and our campus, the College is now closed on Monday September 28.
“Students and staff must return home, or stay at home until further communications via Teams.”
The Holy Cross School in New Malden, south London, said: “Due to a local water supply issue affecting the school site this morning, we have taken the decision to close the school today.”
Thames Ditton Infant School and Long Ditton Infant and Nursery School, Surrey, also said they were shut for the day because of the issue.
Monica Harding, MP for Esher and Walton, Surrey, had told the Press Association on Monday morning: “We need an urgent response from Thames Water to get water supplies back on as soon as possible and to protect vulnerable communities.
“Once the water is flowing again, we need to establish exactly what happened and why.
“My worry is that decades of underinvestment in our infrastructure and poor regulation may be causing incidences like this.”
The MP said on X that her constituency was affected by the issue.
Paul Kohler, MP for Wimbledon, south London, said he had reached out to Thames Water after reports of a water outage across Wimbledon, New Malden, Raynes Park and Morden, in south London.
Liberal Democrat leader Sir Ed Davey said the difficulties faced by households were “yet another example” of the water firm failing its customers.
“Thames Water is already the worst water company in England and Wales for leaky pipes – losing an average of 592 million litres every single day,” he said.
“Meanwhile, 28% of customers’ bills goes straight to servicing the company’s debt, not fixing the crumbling infrastructure that is now failing them.
“The final whistle needs to be blown on Thames Water, and (Prime Minister Andy) Burnham needs to get a grip.”
Some people posted on X saying they had woken up to no water on Monday morning.
“We have no running water,” one user said, before adding: “I just want a shower and a cup of tea. Thames Water want their bonuses.”
Replying to Ms Harding’s post, another user said the outage was “having a huge impact already”.
A Thames Water spokesperson said: “We have isolated the burst main in Molesey and all customers should see their water supply restored shortly if it has not been already, although they may experience some low pressure.
“We are sorry for this morning’s outage and would like to thank customers for the patience they have shown.
“A bottled water station will still be opened this afternoon for customers who require it and we will share its location once it is confirmed.
“Our engineers remain at the site and are working on a permanent repair.”
A straw poll conducted at the entrance to the Labour Party conference in Liverpool on Monday saw 99 of 100 votes cast in favour of public ownership of Thames Water.
Sophie Conquest of campaign group We Own It, which staged an event outside the conference, said: “Hedge funds or households? The choice really is that simple.”
“This Government can choose to sell off one of our most vital resources to US billionaires, or they can take it into public hands and run it in the interests of households, workers and our environment.”
