Over 50,000 people in Kerry have been left without water due to a burst water main.
It's affecting Killarney, Tralee and surrounding areas.
Repairs have been completed overnight, but disruption is likely to continue for several hours.
The area's Water Supply Scheme is one of the biggest in the country.
Independent Kerry County Councillor Niall 'Botty' O'Callaghan told Newstalk Breakfast that water outages are an ongoing issue in the county.
He said: “The situation is very frustrating.
“It has really come to a head in the last couple of months. We have areas like Beara and Farrenfore that are constantly, constantly - a weekly basis - out of water.”
Cllr O'Callaghan said the ongoing major outage leaves around 50% of the county’s population without water.
He accused Irish Water of “not being fit for purpose here in Kerry” and urged the utility to spend more money to fix the county's "antiquated" water infrastructure.
He said: “We had a meeting with Irish Water only four or five weeks ago, and it was the greatest waste of three or four hours of my life.
“They sat there, they listened, and just turned around and said ‘we’ve taken notes… we’ll take it on board’. That’s not good enough.
“If there was an outage like this in Dublin or Cork, it would be sorted, fixed and never happen again.
"All the people in Kerry want is a service - they want water, and to know it’s not going to go down every couple of days.”
Irish Water says they are working alongside Kerry County Council to fix the current issue as soon as possible.
They say the burst pipe has been repaired, and water should return "over the course of the day".
Anna Brosnan of Irish Water said: “Crews have been working hard through the night to complete the repairs.
"We understand the disruption unplanned outages can cause to customers and we appreciate your patience as we work to return the water supply to homes and businesses as quickly as possible.”
Water supply to hospitals is being prioritised, while alternative water supplies will be available in affected areas later this morning.