The water supplies to more than 60,000 homes in Northern Ireland were cut off overnight in a bid to help build up supplies in reservoirs.
Around 2,600 homes still remain disconnected as engineers try to fix burst pipes caused by the sudden thaw.
Affected customers had their supplies cut off for up to 12 hours as Northern Ireland Water (NIW) implemented a rotating on/off supply.
Some of the worst affected areas include Tyrone and Down.
The state-owned company's staff managed to reconnect more than 2,500 homes on Friday, but it was forced to extend the rotation system to other homes despite earlier hopes that the emergency programme would soon be shut down.
Water loss through leaks meant it needed further time to refill the depleted reservoirs.
NIW staff were forced to replace broken tanks in Coalisland, Co Tyrone, on Friday after nearly 5,000 gallons of water were released by vandals.
Louth County Council in the Republic of Ireland has offered to help with the crisis and will supply 10 tanker-loads of water each day from its treatment plant in Dundalk to its neighbour across the border in Newry and Mourne.
Des Foley from Louth County Council said: "We currently have some spare capacity at our treatment plant in Dundalk and - having first prioritised the restoration of supply to locations within Louth - are now in a position to assist our colleagues at Newry and Mourne District Council in accessing a reliable and safe supply of water for homes and businesses in their area."
Meanwhile, the Scottish Executive is continuing to provide Northern Ireland with thousands of litres of bottled water.
As well as repairing the supply network, NIW says it is inspecting private property for leaks. It is urging business owners and landlords to repair any burst pipes as a matter of urgency.
NI Water is responsible for fixing leaking pipes up until the supply enters properties, but it is understood many of the leaks are in unoccupied homes and businesses.
The Regional Development Minister in Northern Ireland, Conor Murphy, has announced an independent investigation into the cause of the crisis.
A full list of areas where the water supply will be turned off is available on the NIW website, along with a list of locations where temporary water supplies have been set up.