Households, farms and businesses in the Timahoe and Ratheniska areas are currently without water supply.
The unexpected cut-off in supply occurred within the last hour without warning.
Local councillors have been contacted by residents affected and are trying to get information on the situation.
LaoisToday understands that the problem has arisen due to a leak in the vicinity of Munny Cross, but the townslands affected are widespread and even as far as Cremorgan.
Irish Water have indicated that they only became aware of the problem at lunchtime and have alerted and dispatched repair crews to the location of the leak at Munny Cross.
A source suggested that they are unable to say when supplies would be restored until the full extent and nature of the problem and damage had been assessed and evaluated.
Only then would they be in a position to indicate how long it will take to carry out repairs and restore service to the community.