Irish Water hopes to restore water supplies to customers on the Coalbrook Supply in East Tipperary this evening.
It is expected that repairs on a trunk water main will be completed later today and supply should be back to most areas by 6pm.
Those in areas of higher elevation may be without water for a longer period as the reservoir refills to build up pressure to supply all areas.
There has been no water since on the network since late Saturday night.
An alternative water supply is provided via tankers at Kilbraugh near the Commons, Ballingarry and at Earlshill near Glengoole South.