Thames Water said they were called to reports of a burst pipe in King Street, Twickenham, at about 11:00 BST.
The water company apologised and admitted a worker damaged the pipe "by accident".
Stuart Sandys, from Sandys Fishmongers, in King Street, said the water had gone "over the roof" of a two-storey building.
A spokesman for Thames Water said: "We're really sorry to people and businesses affected by the burst pipe."
