Four Manchester hospitals cancelled operations scheduled for this morning (February 5) after a burst water main hit supplies.
Patients were last night urged not to attend the Manchester Royal Infirmary, Manchester Royal Eye Hospital, Saint Mary's Hospital and Royal Manchester Children's Hospital this morning while the problem was rectified, unless there was an "urgent clinical need."
Manchester University NHS Foundation Trust said cancer operations would take place as planned, along with any other urgent procedures.
The trust said it was contacting patients and that operations would be rescheduled "as soon as possible".
All outpatient services will be running as usual today (February 5) and anyone with an appointment this afternoon is advised to attend it as planned.
John Martin, spokesman for United Utilities, which provides water to the hospitals, said bowsers (mobile water tanks) were brought in on Saturday to maintain supplies.
He said the pipe was repaired on Sunday evening and the water service was operating as normal.
He said: "All hospitals within the affected area did have water during the course of the repair work but we respect any decision made by the Manchester University NHS Foundation Trust should they feel the need to make changes to their schedules."