A boil water notice affecting 9,500 people in Cork could take weeks to resolve.
Yesterday, Irish Water imposed the notice on homes and businesses supplied by the Whitegate Regional Water Supply Scheme in East Cork following an issue with the filtration process at the plant.
Irish Water apologised to customers and acknowledged the "significant inconvenience the boil water notice will cause" adding it is working with Cork County Council to resolve the situation as soon as possible.
People are being advised to boil all water for drinking, food preparation, brushing of teeth and making of ice, until further notice.
Neil Smyth from Irish Water says the issue will take some time to resolve,
"Unfortunately, it's going to to take time to understand and resolve the problem," he said.
"It's not a matter of days unfortunately, it's going to take a number of weeks to fully rectify the problem and demonstrate confidence that the supply and the treatment processes are all working and robust."