10,000 homes in east Cork remain without drinking water for a third day as a precautionary boil water notice remains in place.
Irish Water has said it is likely to be a number of days before the notice can be lifted.
Testing of the water quality is continuing.
The ban was imposed Sunday on households supplied by the Whitegate Regional Water Supply Scheme due to high turbidity in the Dower spring source, Irish Water said.
People are advised to boil water for drinking, food preparation, brushing their teeth and making ice.
The supply can be used as normal for personal washing and flushing of toilets.
Speaking on RTÉ's Morning Ireland, Irish Water's drinking water engineer for the southern region Conor Foley said the unprecedented level of rainfall since November has highlighted a "vulnerability" in the source.
The boil water notice was issued following consultation with the Health Service Executive.
The areas affected include Midleton southeast, Ballynacorra, Cloyne, Aghada, Whitegate, Ballycotton, Churchstown, Trabolgan and surrounding rural areas.
