Engineers are targeting 2,600 homes still without any water in the North.
Louth County Council has agreed to supply water from its treatment plant in Dundalk to its neighbouring local authority across the border in Newry and Mourne.
The development came as the Scottish Executive continued to supply the North with thousands of litres of bottled water to help cope with the crisis.
Work will continue to restore supply to those caught up in the burst pipes crisis, some of who have been without running water for almost two weeks.
Overnight an additional 60,000 homes were cut off temporarily to allow depleted reservoirs to refill.Some progress was made yesterday reconnecting properties left without any water, with more than 2,500 getting supply back.
But with water still pouring out of leaks in the system, under-fire government-owned utility Northern Ireland Water (NIW) extended its on/off rotation system to other homes overnight in order to replenish reservoirs.
This is despite earlier expressing hope that the rotation would soon be discontinued.
While 500 NIW staff battled round the clock to restore supplies to the region’s crippled system, vandals were yesterday blamed for emptying out almost 5,000 gallons of water from temporary tanks in one of the badly hit areas in Coalisland, Co Tyrone.
People arriving at bowsers at the Gortgonis Park centre to collect drinking water yesterday morning found that the valves had been opened overnight.
NIW replaced the tanks in the afternoon.
Away from Coalisland, the areas worst affected by the water failures are Cookstown, Co Tyrone, Hannahstown near Belfast, and Burren and Warrenpoint in Co Down.
Arctic weather conditions, followed by a sudden thaw, caused large numbers of burst pipes in buildings and in the mains supply, draining unprecedented amounts of water from the system.
While NIW has responsibility for leaking pipes on the main system, that responsibility ends when the supply enters properties.
However, many of the leaks are understood to be within unoccupied homes and businesses and NIW has urged customers to check their properties and repair any bursts as soon as possible.
Stormont’s Regional Development Minister Conor Murphy has set up an independent probe to examine the causes of the crisis, but insisted that restoring water supplies to homes and businesses remained the first priority.