The Big Brother house had to be evacuated on Tuesday after heavy rain flooded part of the reality TV show's compound in Hertfordshire.
The nine contestants who are still participating in the Channel 4 show were taken to a "holding area" within the house as a "safety measure".
They spent the night in the task room after rain leaked into the bedroom.
The contestants were allowed access to all areas of the house on Wednesday night after the problem was remedied.
A Channel 4 spokeswoman said industrial machines had been used to dry out the affected rooms.
Parts of the house, including the living room, the bedroom and the diary room, had been out of bounds for much of the day.
A statement on the Big Brother website said on Wednesday: "The BB team are working as quickly as possible to get them back into the house and we're hoping that should be later today.
"Engineers are currently checking every single cable within the building and double checking everything is in order and safe for our housemates before they return."
Live online streaming resumed after temporarily failing.
The housemates discovered the rain was pouring in on them while they were lying in bed.