Irish Water has extended the national hosepipe ban for another month, until August 31.
Night time restrictions in the Greater Dublin area have also been extended for another two weeks.
Irish Water says the situation will remain critical up to and possibly beyond mid-August.
It comes as Met Éireann has issued a status yellow rainfall warning for Leinster, Cavan, Monaghan, Donegal and Waterford, which comes into effect at 9pm.
But Kate Gannon from Irish Water says it is not enough to restore supplies.
She said: "We would really need 2-3 weeks of heavy rainfall to get our sources back up.
One weekend of rain, even if it is a lot of rain will not give us enough water that we need nationally to help all our sources recover.
Earlier: Irish Water meeting to discuss potential extension of hosepipe ban
Irish water is meeting this morning to discuss the potential extension of the hosepipe ban.
It was due to finish on July 31, but with water supplies still, at critically low levels, there is a chance it could continue for the foreseeable future.
Rain is forecast for the weekend, but it is not expected to be enough to restore supply.
However, Liz Gavin from Met Éireann says it will improve soil moisture.
She said: "We are going to see some heavy bands of rain pushing in from the west later on today and overnight as well. Water deficits are still remaining high in parts of Leinster and Munster but we will see some improvement over the weekend."