Dublin City Council has said that water restrictions will remain in place for the next week because the recovery of water levels at its reservoirs was less than expected last night.
City Engineer Michael Phillips said that 20m litres of water had been saved last night, which was half the amount the council had hoped for.
The council wanted to stagger the restrictions so that affected areas would only be without water on alternate nights.
Mr Phillips also said that so far no major incidents had been reported as industry and businesses got back to normal today after the Christmas and New Year break.
He said the council would have a good idea by midday tomorrow of how the city's system was coping with the increase in demand for water caused by the return of businesses.
The Department of the Environment has said that water supply has stabilised across most of the country.
However, restrictions are still in place in a number of areas, including in counties Cork, Laois and Sligo.
Limerick County Council has announced it is to shut off water supplies in parts of the county overnight, and Leitrim County Council said it still had supply problems.
Up to 1,000 households and farms in southeast Co Galway are without water since St Stephen's Day.
The rural areas are served by the Ballinasloe Regional Water Supply Scheme.
Galway County Council says it is making every effort to return the water supply in a phased basis over the next day or two.
In the midwest, water supplies are continuing to improve but problems remain in particular areas.
Clare County Council says it estimates that around 200 households in the county are still without water.
Problem areas include the outskirts of Ennis, Shannon, Cratloe and Crusheen. The council believes it will be another two days before supply returns to normal.
The next big test for supply will be next Monday, when schools around the country reopen.
Minister for the Environment John Gormley said efforts were being made to replace old pipes, but it would take at least ten years to upgrade the current system.
Severe weather to return
There are renewed warnings of icy weather returning this week.
Met Éireann is forecasting falls of snow and sleet over much of the country on Thursday night and Friday morning with up to 10cm of snow in many areas.
The December cold snap and subsequent thaw caused widespread disruption to water supplies, the effects of which are still being felt.
Met Éireann says the snow is likely to cause disruption, but is not likely to be as severe as the last freezing period.
Elsewhere, the number of households in Northern Ireland without a mains water supply has fallen to around 150.
Reservoirs are also filling up again, but it will be later today before it is clear if the temporary curtailment of supplies will have to be imposed again this evening.
