The Royal Hospital for Children in Glasgow is to be without running water following a bacteria scare.
NHS Greater Glasgow & Clyde said the supply will be shut off on Thursday between midnight and 04:00.
A second shutdown to allow chlorine dioxide dosing will take place for the same period on Thursday 29 November.
Patients will be able to use commodes and portable toilets while hand gel and bottled water will also be provided.
During the first six months of the year a number of patients were affected by bacteraemia.
And in June bacteria was found in drains at two wards which treat children with compromised immune systems.
More recently patients in wards 2A and 2B were moved to allow experts to carry out investigations.
NHSGGC said the latest work would take place during the night to minimise any disruption.
A spokeswoman said: "This is to allow the planned chlorine dioxide dosing to be carried out.
AdChoices "Clinicians have confirmed that there are no safety concerns and a mixture of cleaning wipes, hand gel, bottled water, portable sinks, commodes and portable toilets will be used during these short periods."