Areas in Wicklow and south county Dublin are affected by the notice
A boil water notice remains in place for 65,000 people in Wicklow and south county Dublin.
It's after a mechanical failure with the chlorine equipment at the Vartry Water Treatment Plant.
The supply still hasn't met drinking water standards.
The HSE say it is a precautionary measure and Irish Water are trying to resolve the issue as soon as possible.
The utility said water must be boiled before drinking, washing foods, brushing teeth or making ice.
Irish Water just last week turned the sod on the construction of a new pipeline from the Vartry plant to Callowhill.
The €29m project will see a 150-year-old tunnel being replaced.
The utility was granted planning permission in February 2017. Works are due to get underway later this year and are due to take two years to compete.