A hosepipe ban is currently in place from today.
Householders will be banned from using hosepipes to water the grass or wash their car.
Irish Water says it is introducing the measure in the wake of the driest May since 1850. The ban will be in place until July 21.
They said: "Of Irish Water’s 900 drinking water schemes, 27 currently are in drought and 50 are at risk of going into drought.
"The weather forecast is for a continuation of drier than normal conditions which will further exacerbate the situation."
The utility added that it is making progress on reducing the number of leaking pipes after criticism that that may have contributed to the shortage.
Irish Water said: “The amount of rainfall needed to replenish supplies varies around the country and is site specific however Irish Water estimate that a minimum accumulation of 100mm rainfall spread over a number of weeks would be required and normal rainfall levels after that before the threat to water sources would pass.”
The ban “prohibits the use of garden hosepipes and other non-essential uses of water by domestic users and commercial premises for non-commercial activities for example watering gardens attached to a business premises.”
Tom Cuddy from Irish Water says that among the ways a similar ban was enforced in 2018 was neighbours contacting them.
He said that they got information from source on the ground where they have around 4,000 staff.