Ten fire engines and around 70 firefighters were called to a burst water main in Broadway, Stratford.
The Stratford Centre has been closed and around 50 individual retail units inside the centre have been affected by flooding. The road is flooded to a depth of around eight inches, and the shopping centre concourse is also flooded.
Crews are using sandbags to prevent flood water from entering properties.
Station Manager Clinton Walsh, who is at the scene, said: “The Stratford Centre has been closed as the concourse has flooded.
"It will remain closed for the rest of the day and is likely to be shut tomorrow.
"Thames Water has said residents in E7 and E15 Newham and E11 Waltham Forest will be affected with low water pressure until further notice.
“Crews worked hard to try and prevent flood water from entering the properties.”
The Brigade was called at 0917 and the incident was over for firefighters at 1656. Fire crews from Stratford, Plaistow, Leyton, Poplar, Homerton and surrounding fire stations are at the scene.