This is the shocking moment a water pressure container explodes while friends are relaxing in an apartment.

The tank had been installed in the building in Nanyang, Henan, China, to combat low water pressure in the flat complex.

CCTV footage shows three friends chatting and drinking next to the pressurised vessel. Seconds later, it suddenly bursts like a bomb, drenching the stunned men and flooding the entire room.

The force of the blast is so strong that the unit is ripped from its mountings and flung to the floor.

Flat owner Mr Zhao said he had bought the pressure booster five years ago.

He added: 'The merchant didn't tell me it was second-hand.'

Reports said Zhao sustained a hand injury but was otherwise unharmed on May 6.