Update- 1.10pm: Irish Water says it cannot rule out daytime restrictions as it battles to restore levels across the country.
Its crisis management team is meeting this afternoon with nighttime restrictions due to come into force from Monday.
Irish Water will reduce water pressure between midnight and 5am from Monday night in parts of Dublin, Wicklow, Meath and Kildare.
However, the exact areas affected are still being worked out and won't be known until this afternoon.
It says although the nationwide hosepipe ban is working, levels are still critically low and there's no significant rainfall on the way.
Update 9.40am: 'Daytime restrictions a last resort' - Irish Water
Irish Water says there will be no daytime restrictions in the greater Dublin region - for now.
It plans to reduce water pressure between midnight and 5am from Monday night - but the areas affected will not be known until later today.
It says the nationwide hosepipe ban is working - but levels are still critically low - with no significant rainfall forecast.
We are working with the local authorities in the Greater Dublin Area to introduce night time water restrictions in order to protect future supply and avoid widespread outages. A final decision is expected tomorrow. See https://t.co/I1vllqiXEo for more. #ConserveWater— Irish Water (@IrishWater) July 12, 2018
Irish Water's Eamon Gallon says further restrictions cannot be ruled out.
He said: "At the moment we can't predict how far we have to go, we are hopeful to keep it during nighttime.
"We might extend the amount of time during the night, we might go from pressure reduction to more severe pressure reduction or even cut off the water supply during the night.
Earlier: Nightime water restrictions in place for Dublin next week
Dublin will have nighttime water restrictions from early next week.
Irish Water says it has made the decision to protect future supply and avoid widespread outages this autumn.
The company's Kate Gannon says it will announce details today on where the restrictions will be and for how long.
She said: "Restrictions will happen in the Greater Dublin area, it is likely they will start from next week.
"Our operations teams are looking at how that would be rolled out to try to maximise the amount of water that can be conserved while minimising the impact on homes and business in the area."