Water engineers are continuing to work around the clock in a bid to reconnect supplies to thousands of users in Northern Ireland.
Government-owned Northern Ireland Water, however, said it would be "at least three or four more days" before everyone was back on supply.
Some people have now been without a water supply for two weeks.
On Sunday evening, supplies to more than 55,000 households will be cut off in order to help replenish reservoirs.
However, NI Water has reported that the number of homes and businesses with no supply has dropped to 799.
Burst pipes are expected to cause disruption at some schools scheduled to re-open on Monday following the Christmas break.
Meanwhile Scottish First Minister Alex Salmond said he would not be charging Northern Ireland for the 500,000 litres of bottled water sent over during the crisis.
The areas affected include east Belfast, Dungannon and Aughnacloy.
Dunmurry, Castlewellan, Newry, and Ballygawley have also been placed on a rotating supply.
Parts of Belfast as well as customers in the Ballygawley/Aughnacloy area had their supply curtailed for a limited period on Saturday and Sunday.
As of 1000 GMT on Sunday, NI Water said the number of customers without any supply has been reduced to 2,497 properties.
However, the overnight switch-off added thousands more homes and businesses to those numbers.
A full list of areas where the water supply will be turned off is available on the NI Water website, along with a list of locations where temporary water supplies have been set up.