Firefighters dealt with a burst water main at the Crooked Billet Roundabout in Chingford.
A 300mm water main burst on a footpath, flooding the pedestrian underpass at the roundabout to a depth of about a metre.
Crews used a portable pump and sandbags to divert the flood water to the main drain. No properties or the main road were affected by flooding.
The Brigade was called at 0800 and the incident was over for firefighters at 1110. Fire crews from Walthamstow, Chingford, Woodford and Leyton fire stations attended the scene.