LEWISHAM fire station’s fire rescue unit is in Herne Hill dealing with a burst water main with the water up to a metre deep in some places.
More than 100m of road is flooded and firefighters are using dinghy style boats to get around the flooded area.
The water main in Half Moon Lane has been switched off and the water is slowly receding.
A London Fire Brigade spokesman said: “Our crews are well equipped to deal with floods, and we have lots of specialist skills and equipment used at the scenes of incidents like this one.
“The most important thing for us is making sure that people are safe, so people who live in the affected street are being advised to stay in their homes until the water is cleared.
“Then we will be helping to clear water out of basements, homes, and local businesses."
As well as Lewisham firefighters, a fire rescue unit from Battersea fire station is at the scene along with fire engines from Brixton and West Norwood.
The brigade was called just before 5am today (August 7).
Dulwich Road, Milkwood Road and Norwood Road have also been affected and road closures are in place.
Motorists and other members of the public are advised to avoid the area if possible.