A major water leak will mean supplies being switched off at the Queen Elizabeth Hospital, in King's Lynn.
Contractors called in to investigate sodden ground near the Sandringham Hospital, on the QEH site, found a main had spring a leak.
But as they dug around to it to survey the damage this morning, the pipe ruptured and a trickle of water became a flood.
This lunchtime, a QEH spokesman said an estimated 60L of water a second was now escaping.
'It was a section of ground that had been feeling spongy for some time, so we knew we had a leak somewhere,' he said. 'So we called in contractors to investigate.
'They dug an hole and found a pipe where there was a leak, but it released the pressure and made it worse.
'We've had to shore up the hole with timber as best we can. It's not affecting hospital services but it's a matter of concern, as we're obviously losing quite a lot of water.'
Services at the hospital are not being disrupted by the leak. It was originally hoped that water would be turned off tonight, so contractors could repair the main.
But this afternoon, the QEH said it would have to arrange alternative supplies for wards, which would take until tomorrow night, before the main could be repaired.
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