Irish Water has insisted there will be no daytime restrictions in the greater Dublin region - for now.
The utility plans to reduce water pressure between midnight and 5am from Monday - but the areas affected will not be known until later today.
The decision was taken in an attempt to protect future supply and avoid widespread outages this autumn.
While Met Éireann expects the drought conditions to lift somewhat over the coming days, the recent dry weather is continuing to put pressure on water supplies.
Irish Water said the nationwide hosepipe ban is working - but levels are still critically low - with no significant rainfall forecast.
The utility’s Eamon Gallon said further restrictions can't be ruled out:
“At the moment we can’t predict how far we have to go,” he said.
“We are hopeful to keep it during night-time.
“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.
“Daytime restrictions or daytime outages would be a last resort.”
Announcing the restrictions last night, spokesperson Kate Gannon said: "We are monitoring the situation, but the weather is not changing, the rain is not coming.
“Something else has to be done to protect water supply and avoid widespread outages in the autumn.”
There are over 20 water schemes across the country already on restrictions, and a national hosepipe ban remains in place.