The new report says water supply at the plant is not as resilient as it needs to be.
A new report says significant failures in oversight and management by Irish Water and local authorities last year put the health of the 885,000 people served by the Ballymore-Eustace and Gorey water treatment plants at risk.
Some 55 people were hospitalised last year after drinking tap water in Gorey.
However, according to the latest Environmental Protection Agency report, the quality of public drinking water supplies in Ireland remains high, with more than 99.7% compliance with bacterial and chemical limits.
The agency said this is positive for consumers and indicates that the water is safe to drink.
The EPA said many water supplies are not as resilient as they need to be, including those serving 316,000 people in Ballymore Eustace, Wexford Town, Cork city, and Limerick city, - all of which are currently on the remedial action list.
The EPA said the length of time it is taking Irish Water to address such issues is unacceptable.
Noel Byrne, programme manager with the EPA, say boil Water notices are also likely to increase this year, but Irish Water management systems need to be improved: