A nationwide hosepipe ban will come into effect from tomorrow morning.
The measure is already in place in the greater Dublin Area, but Irish Water has decided to extend it to the whole country until the end of the month as supplies remain under pressure from the heatwave.
Most parts of the country will enter a state of "absolute drought" today meaning no rain has fallen in the past 15 days.
Using water for non-essential activities is banned under the order and anyone who breaks it could face prosecution or a fine.
Irish Water says more restrictions may be put in place, as supplies remain under pressure. However, demand has dropped since the order was introduced in the Greater Dublin Area earlier this week.
Managing Director of Irish Water Jerry Grant says further action may be necessary.
Mr Grant said: "We could begin to exclude other uses. We'd be very reluctant at the moment to exclude anything that involved employment or commercial activity.
"We do have that power, but there are rigours we have to go through to demonstrate the absolute case for it. We'll keep that under review obviously."
Irish Water's Eamon Gallen says they will send people round to households that consistently ignore the ban.
Mr Gallen said: "We've had very few reports so far of people breaching the ban. In cases where there is consistent and excessive usage, we will send people out to investigate if there are problems or leaks on the property and whether or not we can give conservation advice.
"It's not our intention to be imposing fines in any great number, we believe that once we talk to people, we can change behaviour, and most people that are law-abiding will adhere to the order."
Meanwhile, night time restrictions are also planned for several areas over the coming days.
This includes Westmeath, Offaly, Louth, Longford, Laois, Galway, the Aran Islands, Donegal, Limerick, Kilkenny and Cork.
Full details can be found on Irish Water's website.