A forgetful Highfields tenant returned home from a shopping trip to discover her hallway full of furious neighbours and firemen after a tap left running flooded the homes below hers.
Water continued cascading from the bathroom tap through homes all the way to the ground floor, in Hunter House, Feltham, and damaged at least four properties.
Downstairs neighbour Kirsty Foreman said: "I was the first person to notice it. I just heard this tap, tapping sound and realised it was water coming through the ceiling. I'm absolutely furious. This is the second time this has happened since we moved in September. Everyone was upstairs in the corridor shouting and banging on the door."
The flooding, which happened over three hours on Monday afternoon, was only located once firemen broke down the door and switched it off.
Watch manager Phil Watkins, of Feltham fire station, said: "We traced the leak to a flat on the eighth floor, where water was also flowing out into the hall. No one was in so we had to break the door down to get to the tap."
A spokeswoman for Hounslow Homes, who manage all the properties involved, said: "The cost of the repairs is not clear as yet. We would advise all residents to ensure that they have not left any taps, cookers or washing machines on, before they go out."