Pictures from the area show emergency services parked by the side of the impromptu river, while cyclists have tweeted pictures showing dirty water lapping at their wheels.
Other photos show water gushing through the gates of Kennington Park, which flanks the main road.
A Thames Water spokesman told the Standard: "We have a team on their way to investigate following reports of a burst water pipe."
Travellers took to Twitter to joke about the deluge, which comes as London is expecting the biggest heatwave of the year.
Jen Conway tweeted: "Kennington Park now has a moat," while Moth Titty wrote: "Kennington now partly underwater due to a burst water pipe. Nothing like a quick swim to cool off before work."
