Big Brother housemates sheltered in the bedroom after heavy rain caused water to flood through the roof of the TV house.
Evelyn Ellis, Sam Giffen, Emma Jensen and Andy West had been outside dancing in the rain when the water started pouring in through the living room ceiling.
They ran inside when they heard Lateysha Grace shrieking about the flood.
Property developer Jason Burrill ordered everyone to stand back, before Big Brother said they were to stay in the bedroom while the show's technicians tried to deal with the problem.
Presenter Rylan Clark-Neal tweeted: "CANT BELIEVE what I'm seeing. The @bbuk house has flooded! It's literally WET WET!"
The flood prompted speculation the contestants would spend the night in the "Other" House, which was initially home to six extra contestants.