Dublin City Council has warned that the water supply situation is an emergency and that night-time restrictions look set to continue.
The council started three nights of water supply restrictions on Tuesday and said it will review the situation tomorrow.
However, today the council's Director of Traffic Michael Philips said they may have to continue over the weekend.
Mr Philips said that night-time restrictions introduced by the city council and the three other Dublin authorities had succeeded in bringing demand back down to meet supply.
But he said that restrictions may have to continue to replenish water reserves.
Mr Philips rejected criticism by some business groups about a lack of notice of the night-time cut-offs, saying it is an emergency situation.
He said businesses have 12- to 24-hour water tanks and that ground floor businesses would only be facing a loss of pressure at night under current restrictions.
Meanwhile, Wicklow County Council is also restricting water supplies overnight in a bid to conserve supplies.
Tonight the water supply will be turned off in parts of Kilquade, Kilpedder, Kilcoole, Blessington, Wicklow town and Arklow.
The council says there has been a huge increase in demand for water in the past week.
It has appealed to residents to help by reducing their water usage to the lowest level possible.