Irish Water has issued a stark warning asking people to keep conserving water.
The utility says that supplies could run out of one of the main resevoir's after 70 days, depending on how dry the Autumn is.
At the moment, there's currently restrictions in place in the Greater Dublin Area, while a hosepipe ban remains in place across the country.
Levels have been reaching critical levels in a number of supplies nationwide following the recent heatwave.
Managing Director Jerry Grant says: "On about the 10th or 12th of May, we had 150 days storage in Poulaphouca - it's an enormous source of water and it saves the city year-in, year-out.
"We used 80 days of that storage in 83 days. In other words almost nothing was contributed to the storage in that period.
"We've about 70 days of useable water left for the Greater Dublin Area - 1.6million people.
"We could be 90 days before that lake starts to rise, depending on how dry the Autumn is."