A burst water main has flooded to up to 100 homes in south-west London and left thousands without water.
Some parts of Colliers Wood were under several feet of water
Thames Water says 7,500 customers have reported no water or low pressure after a pipe burst in Colliers Wood at about 0300 BST on Wednesday.
Eyewitnesses said torrents of water flooded flats and houses near the burst main at the junction of Cavendish Road and Devonshire Road.
And there were delays for commuters as the A24 closed and Colliers Wood Tube station shut.
Resident Susan MacMillan told BBC News Online: "The water was charging past our house. You could just take your cup outside and fill it up."
Water supplies were cut off to homes and businesses as far out as Tooting and New Malden.
Thames Water said they were gradually being restored throughout the afternoon.
But low pressure and air locks are likely to continue, particularly at tea time when demand is highest.
Loss adjusters will be visiting flooded properties to deal with claims for damage.
Shelly Ostler's family woke up in the middle of the night to find water seeping through the letterbox and flooding the ground floor.
She said: "You don't know what to do. You are just stuck here. You can't leave the house.
"My neighbour upstairs has been lovely, she's been making me tea and looking after me and [letting me use] the telephone. My telephone is in the water."
A spokeswoman for Thames Water apologised to those affected by the flooding and water shortages.
She said a team of 15 people had been working through the night to stop the flow from the pipe.
"As for the reasons for the pipe bursting, we are not really sure. At the moment it is most likely to be down to changes in temperature and pressure," she said.
It follows a burst pipe in the Southwark area of south London two weeks ago which left up to 4,000 homes without water.