A Qantas flight was forced to turn back to Los Angeles after a burst drinking water pipe flooded part of the cabin. The Airbus A-380 was an hour into the flight from LA to Melbourne when it turned around.
Qantas said passengers were moved to "unaffected areas" of the plane and given blankets to stay dry and "the captain decided to return to LA in the interests of passenger comfort".
"Crew on board did everything they could to help customers," Qantas said in a statement.
The airline said it was discussing the problem with Airbus.
The Aircraft Engineers Association's Stephen Purvinas said it was a serious safety breach.
"If it had have leaked down onto the electronic components it could have brought the thing down," he said.
However, Qantas spokesman Andrew McGuiness said passenger safety was not at risk.