Multiple road closures are in place in north London after a 36-inch water main burst, causing flooding up to four-foot deep.
Emergency services were called to the scene in Islington at just after 7am on Monday, London Fire Brigade (LFB) said.
Ten fire engines and around 70 firefighters are attending the scene on Hornsey Road.
Station commander Matt Brown, who is at the scene, said: “Flood water is affecting Hornsey Road, Tollington Road and a leisure centre.
“There are multiple road closures in place whilst crews work to make the scene safe. People are urged to avoid the area.
“Firefighters are using flood barriers to divert water.
“If you are affected by flood water, if possible (and without putting yourself at risk) move to a higher level.”
A Thames Water spokesperson said: “We’re sorry to customers experiencing lower pressure than normal or no water this morning due to a burst pipe.
“Our engineers were quickly on the scene and have stopped the flow of water, which is now draining away.
“We’re doing all we can to get things back to normal as quickly as possible and we’re pro-actively contacting everyone in the affected area who has pre-registered with us as having special requirements, such as being medically reliant on water, so we can make sure we give them the help and support they need.”
Chris Dodsworth, a civil servant who lives in the area, described the situation as “quite stressful” and that the water levels appear to be rising.
He told the PA news agency: “I woke up around 7:30 and realised I could hear the sound of running water outside which was obviously strange, especially given the weather recently.
“My first thought was that it had rained overnight but then I obviously glanced out the window and just saw that the whole street and connecting roads were utterly submerged.
“It’s so strange to be around so much water (especially in this time of drought)…what a day of contrast.”
Liz Clutterbuck, 41, a vicar at Emmanuel Church, told PA: “The flood stretches all the way to Arthur Road. The houses between Arthur Road and Tollington Way have water above the bottom of their front doors.
“The Sobell (leisure centre) is flooded by several feet – could see it at least two feet high on the external exits in the car park. Water still seemed to be flowing fast an hour ago.”
Reverend Clutterbuck added that the church is open for residents to use if they need to.
“The fire service were down very quickly and we hope, along with Thames Water, they can get things back to normal as quickly as possible.”
A spokeswoman for GLL, the charitable social enterprise that operates the Sobell on behalf of Islington Council, said the lower ground floor of the building had flooded, prompting staff and customers to be evacuated and the building to be closed for the day.