The notice was issued earlier this week.
The boil water notice affecting 600,000 people will stay in place until at least Tuesday, November 12.
According to Irish Water, the notice issued for people living in parts of Dublin, Meath, and Kildare will not be lifted until at least early next week due to problems affecting water quality.
According to RTE News, tests carried out today to determine water quality returned satisfactory.
However, the Environmental Protection Agency (EPA) and the Health Service Executive (HSE) wish more tests to be conducted before the notice is lifted.
Irish Water confirmed earlier this week that the second boil water notice was being issued for the surrounding areas of the Leixlip Treatment Plant due to weather conditions.
“Due to heavy rain, turbidity (cloudy water due to suspended particles levels) in the source water for the old Leixlip Plant exceeded acceptable levels,” they said in a statement.
“Plant operators reacted quickly before alarms were activated and shut down the old plant to stop this water entering the network. There were no issues at the new plant, where the level of turbidity was managed by the newer technology on site.
“It was essential to re-start production at the old plant, which produces 20% of drinking water for Dublin, otherwise significant restrictions and outages would be inevitable.
“As Irish Water cannot guarantee the quality the water from the old plant, a Boil Water Notice is now in place.”
