Irish Water has said 16,000 people are without water in counties Tipperary, Galway, Wexford and Leitrim.
Water restrictions meanwhile, are in place for 37,000 households in Leitrim, Meath, Galway, Mayo and Cork.
Almost 15,000 are on boil water notices - mainly in Enniscorthy, County Wexford.
12,000 households supplied by the Fethard Public Water Supply in County Tipperary are on a "Do Not Drink" notice.
Reduced pressure in parts of the greater Dublin area will continue tonight from 8pm until 6am.
The utility has said that aging condition of its pipes "particularly in the Dublin region" has contributed to the widespread outages.
As of yesterday, three major bursts in Dublin which were wasting the equivalent of the daily water usage of Balbriggan had been repaired.
It said the decision to reduce pressure across the greater Dublin region last night was not taken lightly - but warned it had to act to "ensure the city continued to function."