A contestant says he has been unable to train for the Ninja Warrior UK TV game show because blocked street drains flooded his Gloucestershire gym.
Dion Trigg, who is preparing for the ITV show, said he was devastated when his gym ended up "completely under water" following a flash flood.
He claims nearby drains in Chalford have been filled with silt for a year and feels "completely let down".
Severn Trent, apologised saying it was due to a "manhole cover overflowing".
Mr Trigg, who has appeared in two series of Ninja Warrior UK, set up his own gym five years ago which helps train people for the show. It is also used by at least 20 former contestants.
He said it was "quite clear" that blocked street drains had caused water to cascade down Cowcombe Hill on Tuesday, filling his gym with silt, mud and "filthy water".
"I train at least six days a week and had all my training planned out for Ninja Warrior UK five but now I'm not able to train," he said.
"I also train people from all over Europe who are applying for the show this year and I'm having to tell them I don't know when I'm going to train again.
"I am completely devastated."
But in a statement, a Severn Trent spokesperson said the flooding was caused by a "manhole cover overflowing in Chalford after the heavy rain on Monday".
"Engineers have been out to the site to get things cleaned up and the sewer system appears to be working normally again," he said.
The Ninja Warrior UK series, which is described as being tougher than Gladiators, is based on the Japanese show Sasuke.