Uisce Eireann has issued the warning in a worst-case scenario.
Homes and businesses could be without water supply for up to 150 days a year by 2049.
Uisce Eireann has issued the warning in a worst-case scenario.
Households could face around 80 days outages per year from the mid-2040s due to higher than expected demand for water and supply challenges.
This would increase to about 150 days for the average household by 2049.
Uisce Eireann's report says that's if nothing is done to tackle infrastructure deficits.
Current water supplies and capacity in the greater Dublin area would not be sufficient to prevent mass outages in future.
The Oireachtas Committee on housing recently heard how water supply to Kildare, Wicklow and surrounding areas is too dependent on the River Liffey, which is vulnerable to drought and contamination.
Uisce Éireann CEO Niall Gleeson informed the committee that the Liffey, serving 1.7 million people, cannot meet future demands.