Water is slowly returning after repairs to a pump that failed at the Listowel Regional Water Treatment Plant in north Kerry have been completed.
The disruption to the water supply had left thousands of households in the area without water.
However, reservoirs are now refilling and water is now gradually returning to Listowel, Tarbert, Moyvane, Knockanure, Lisselton, Finuge, Lixnaw and surrounding areas.
In a statement, Irish Water said all areas will see their water supply return over the course of the day.
Water tankers had been deployed to some of the affected areas and alternative water supplies had also been diverted to the local hospital, nursing homes and where possible to other businesses in the area.
Irish Water said that replacement parts had to be specially made to carry out the repairs.
It said that senior officials from Irish Water and Kerry County Council "will continue to monitor the situation closely as water supply returns to homes and businesses."
Margaret Attridge, Operations Manager at Irish Water said that 4,000 people were affected by the water outage.
Irish Water said in a statement that work will continue on implementing a back-up pumping system so that the necessary resilience is in place for securing the supply.
"We will be implementing a full replacement of these pumps as part of an upgrade programme and the timing of this replacement is being reviewed by Irish Water following this incident," the statement said.
Irish Water said that water tankers will continue to be available at the following locations today until full service is restored to customers.
- Listowel - The Square and car park at Kerry County Council offices
- Lisselton - Car Park at Lisselton Cross
- Lixnaw - Church Car Park
- Knockanure - Church Car Park
- Finuge - Car Park at GAA Grounds
- Moyvane - Church Car Park
