The Scottish government has begun the process of delivering bottled water to help supply Northern Ireland households cut off from mains supplies.
Water from bottling plants in Banff and Forfar will be loaded onto the Larne ferry later on Wednesday.
The move follows an agreement between the Scottish Government and the Northern Ireland Assembly.
The delivery of about 160,000 litres of bottled water is being carried out by Scottish Water.
Scotland Minister for Transport and Infrastructure Keith Brown said the Scottish government was pleased to be able to offer the support to Northern Ireland.
"Scotland understands only too well the impact of severe winter weather on households and infrastructure. At a time when 40,000 households across Northern Ireland are without water supplies we are pleased to be able to extend this support to a friend and neighbour in need," he said.
"The continuing thaw has seen a four-fold increase in calls to Scottish Water from householders and businesses dealing with burst pipes in Scotland."
Peter Farrer, Scottish Water's customer service delivery director, said the support provided to Northern Ireland would not hamper efforts to deal with Scotland's own water problems.
"We understand completely that homes and businesses in Scotland are without water because of leaking or burst pipes, however this helping hand to our neighbours will not affect our service to our customers in Scotland," he said.
"We have been working at full capacity for several days, and drafting in extra resources to deal with the impact of the extreme weather in Scotland. This has involved responding to leaks, delivering bottled water and providing advice.
"None of this frontline response will be diverted in Scotland to handle this request. Neither will it impact on our ability to deal with any water supply issues that arise in Scotland.
"We are confident that Scottish Water customers will appreciate that the situation in Northern Ireland is truly exceptional and that it is right that any assistance available is offered."