Up to 80,000 homes are facing another night without power as a further 100,000 people have been left without safe drinking water in the wake of the ferocious Atlantic storm.
As efforts continue to restore electricity to 115,000 homes and businesses, mostly across the south and west, Limerick County Council was forced to order a widespread boil water notice as a precaution.
Electricity supply chiefs in ESB had earlier warned that repairing power cuts to major infrastructure - such as water treatment plants - were one of its top priorities.
Limerick County Council said the boil notice was a precaution on the advice of the Health Service Executive and Irish Water.
"The council is not in a position to guarantee that water supplies throughout the county are treated to the standards required by regulations," a spokesman said.
Water supplies in Limerick city and suburbs under the authority of the county council were not affected by the notice.
The County Council said it would continue to liaise with health chiefs with a view to lifting the boil notice as soon as practicable but it was likely to remain in place for a number of days.
The warning called for all water to be boiled rigorously if it was for d rinking; for p reparing foods not to be cooked; for b rushing of teeth, and for ma king ice.
Limerick County has a population of 135,000 but it is not clear exactly how many homes and businesses are facing the boil notice.
Also in the west, Clare County Council has begun sending tankers of water to five towns after shortages in supplies in and around Sixmilebridge, Cratloe, Kilmurry, Kilkishen and Killaloe.
"The council is in ongoing engagement with the ESB and Irish Water, who have confirmed that they are working to address the issue," a spokesman for the council said.
Limerick city has been unaffected, with areas under the authority of the County Council such as Dooradoyle, Raheen and Castletroy and university not included in the boil notice.
Meanwhile, ESB warned between 60,000 and 80,000 would face a second night without power as it focused efforts on high voltage cables.
Helicopters have been deployed by the electricity company as 2,000 repair staff search for the worst-hit areas, supported by crews from Northern Ireland and outside contractors.
Power has been restored to over 145,000 customers since the peak of the storm yesterday, but up to 80,000 will face another night without electricity.
Denis Cambridge, southern divisional manager for ESB, said they were facing a massive operation after one of the worst storms on record.
"This is one of the biggest clean up operations I have ever experienced, and we have pulled resources from every part of the company and beyond to get the lights back on as quickly as we can," he said.
"It is a mammoth task.
"In Cork and Kerry alone we have over 3,200 individual faults to get to, and we are working against the clock before the next of the bad weather sets in tomorrow."
ESB warned it could make no guarantees about when power would be restored to homes.
It was telling people who needed 24 hour power for medical or emergency needs to make other arrangements.
Such is the damage, 1,000 wooden poles, over 250km of conductors and 400 transformers are needed to restore the electricity cable network.
Fallen trees and timber also needed to be cleared from around 2,000 locations around the country.
Some 60,000 people were also without telephone and communications at their homes and businesses.
West Cork and Kerry have been singled out as the two regions which bore the brunt of the weather system and saw near record winds gusting to 177 kilometres per hour inland.
ESB said its crews were working through driving rain and difficult conditions with the focus on supplies in Kerry, Cork, Limerick, Tipperary, Wexford, Waterford, Clare and Laois.
Helicopters have flown out of Dungarvan, Co Waterford, and Kilcullen, Co Kildare, to examine lines and assess damage to the network.
The aerial patrols were tasked to traverse the south of the country, from the south-east towards Limerick and Clare, and into Cork and Kerry.
The Government's National Coordination Group met this morning to review the damage done to communities up and down the country and to transport and energy services.
"ESB have advised that it deployed 2,000 staff to deal with power outages, and it could take a number of days to restore power to all areas as some of the infrastructure is in remote areas and access problems may hinder them," the unit said.
Repair teams have been tasked to prioritise power to major infrastructure such as water treatment plants and pumping stations as these facilities can cause public health issues first.
High voltage supply lines are also top of the agenda before works begin on the more local supply chain.