Irish Water has confirmed that the boil water notice for parts of Dublin, Kildare and Meath has been lifted with immediate effect.
Irish Water said this afternoon that the Environmental Protection Agency had conducted an audit of the Leixlip water treatment plant on Thursday.
It said test results of a water sample taken earlier in the week were found to be satisfactory and this result formed part of the audit process.
Earlier today, the results of two more water samples taken later in the week were received.
It said both samples were satisfactory.
Yvonne Harris Head of Customer Operations at Irish Water said: "Irish Water acknowledge and understand the impact of this boil water notice on the 600,000 people affected and we sincerely regret the inconvenience."
Boil Water Notice for customers supplied by the Leixlip Water Treatment Plant has been lifted with immediate effect. We are grateful to our partners in @Fingalcoco who worked with us to provide all necessary detail to the HSE & EPA to facilitate the lifting of this notice. pic.twitter.com/WlipJSCoQg— Irish Water (@IrishWater) October 25, 2019
Ms Harris said that Fingal County Council had flushed the network in key areas to remove the remaining at risk water from the network since early today.
Speaking on RTÉs Drivetime Yvonne Harris said that workers went to the extremities of the network in Howth, Skerries and north county Dublin to ensure all the water had passed through the system.
She said she is confident it can now be consumed as normal.
Ms Harris also said that remedial actions got under way at the Leixlip plant after an EPA audit earlier this year.
She said they will now continue to work with the HSE and EPA.
The Minister for Housing, Planning and Local Government Eoghan Murphy said the boil water notice was necessary to protect the public from illness and was put in place following a consultation between Irish Water and the HSE.
In a statement this evening he said the EPA's final audit report will be published in the coming days.
However, the Minister added: "I am extremely concerned to hear that the EPA found no system was in place to respond adequately to process alarms at the water treatment plant serving a major part of our capital city and surrounding area. Irish Water must now work with Fingal County Council to ensure there is no repeat of this type of incident.
"Once I have the EPA's final report, due in the coming days, I will be meeting directly with the Managing Director of Irish Water and chief executive of Fingal County Council," he said.