Patients have been urged to stay away from four of Manchester's hospitals unless there is an urgent clinical need because they have no running water.
A burst water main on Oxford Road close to the Manchester Royal Infirmary cut water supplies on Sunday.
All non-urgent operations there and at Manchester Royal Eye Hospital, St Mary's Hospital and Royal Manchester Children's Hospital have been cancelled from Monday morning.
United Utilities said it was working to fix the issue and apologised for the disruption.
"Our teams are still on site working hard to repair the burst water pipe," a statement on its website read.
"We do appreciate how inconvenient this must be, and we thank you for your continued patience today.
"As soon as the repairs are complete we will provide a further update, so please keep checking back."