Water tanks were sent to the hospital after the mains burst

A spokesman for Ysbyty Gwynedd, Bangor, said it made use of a back-up system until the supply was restored on Monday afternoon.

The problems meant that there was a shortage of pure water.

The burst pipe also affected properties in parts of Bangor, Penrhosgarnedd, Caerhun and Glasinfryn.

The burst happened early on Monday and Dwr Cymru Welsh Water said its contractors were on site immediately.

Welsh Water said earlier on Monday: "We have located the burst and are now carrying out repairs.

"It is anticipated that supplies will be restored during the course of the day.

"We are currently focusing our attention on supplying special needs customers with emergency water supplies and we apologise to all our customers for any inconvenience caused.

"Ysbyty Gwynedd is utilising an internal emergency water supply.

"Dwr Cymru Welsh Water has sent a water tanker to the hospital to top up this system to ensure continued supplies."

The hospital said a total of 14 operations were postponed and it hoped that it could reschedule surgery as soon as possible.

Meanwhile, pupils at two local primary schools were sent home.

Staff at Ysgol y Garnedd and Ysgol y Faenol in Bangor contacted parents asking them to pick up their children.