John Helliwell, 64, and his partner Sue Broome, 62, re-opened The Singing Man in Shafton at the end of June.
But Friday's heavy rain led to six or seven inches of water whooshing into the pub. The boozer is expected to be closed for about a fortnight.
Mr Helliwell said water came in through the back of the pub over about five minutes.
He added: "Rain water was coming up through grates outside and poured in through fire doors.
"We are gutted. We spent thousands getting the pub going."
** The full story appears in the Barnsley Chronicle, dated August 15. **