Six fire engines and around 40 firefighters were called to a burst water main in Falling Lane, West Drayton.
The road was flooded to a depth of a metre. Around 80 properties and 120 residents were affected by the rising water. Firefighters used sand bags and pumped water away to try and limit damage to homes.
An unwell resident was transported by Fire Rescue Unit boat to London Ambulance Service crews who took him to hospital.
The Brigade was called at 2039 and the incident was over for firefighters at 0143. Fire crews from Hillingdon, Hayes, Heathrow, Feltham, and Southall fire stations attended the scene.