Uisce Eireann is asking people to try to conserve water as levels are running low.
Around Seven thousand customers are without water nationally, down from 30 thousand, as crews are working to access treatment plants.
Reservoirs have also been affected by freezing temperatures, while power cuts are affecting services.
Thousands of homes in south-west Dublin are facing water disruption this afternoon due to a reservoir interruption.
The water disruptions are stretching from Kilnamanagh in Tallaght to Scholarstown Road in Knocklyon and surrounding areas of Dublin 16.
Uisce Eireann say works are scheduled to take place to rectify the fault until 3:30pm this afternoon.
A statement on the water utility's website reads: "A reservoir interruption may cause supply disruptions from Kilnamanagh, Tallaght, Dublin 24 to Scholarstown Road and surrounding areas in Dublin 16.
"Works are scheduled to take place until 3:30pm on 5 January. We recommend that you allow 3-4 hours after the estimated restoration time for your supply to fully return."
The cold snap has seen tens of thousands of homes across the country are also without water today due to the cold snap sweeping the country. Up to 30,000 homes in Kerry, Wexford, Kilkenny, Carlow and Limerick are without water with crews working to restore service.
Uisce Eireann has urged people in those areas to conserve water where possible. The company said: "We are urging households, businesses and farmers to check for leaks and turn off water to outside pipes or unoccupied premises.," the organisation said in a statement.
"Alternatively, people may consider setting the heating for these areas to come on periodically at a lower temperature. This allows warm air to circulate and will help to prevent pipes and tanks from freezing in the cold weather."
Around 24,000 homes are without power due to the big freeze, including 390 in Kildare with ESB Networks currently working to restore power in all areas.
