NI Water has received more than 14,000 calls from people affected by frozen and burst water pipes.
The company is making bottled water available at depots in Londonderry and Craigavon for anyone who has been without a mains supply for 24 hours.
It said some customers may experience a temporary loss of supply or a drop in pressure as repairs are made to pipes.
The Roads Service said it did not carry out salting overnight, but warned of excess water on roads.
The service said many gullies were still blocked with frozen ice allowing water to accumulate on roads.
It has advised motorists to continue to be extremely vigilant.
NI Water said it had received more than 32,000 calls this month and staff had repaired 400 burst water mains.
The main areas affected include Belfast, Londonderry, Dungannon, Omagh, Armagh, Newry and Craigavon.
The SDLP has called for an emergency meeting of the Executive to discuss the impact of the extreme weather conditions on homes and businesses.
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