The alert was issued after elevated chlorine levels were detected
A 'Do not use/Do not consume' water alert that was in place for parts of Co Meath has been lifted.
Irish Water has confirmed that the warning advising people not to drink, use for food preparation or wash has been lifted with immediate effect.
The warning had been in effect for Kilcloon, Moygaddy, Killeany, Kilgraigue, Harristown, Brownstown, Ballynare, Butlerstown, Staffordstown, Brownrath, Blackhall Little, Waynestown, Harlockstown and Ballymacoll.
The alert was issued after elevated chlorine levels were detected in these areas.
Irish Water said it was notified late on Monday night via email that customers were experiencing water quality issues.
The utility said it then telephoned those customers on Tuesday and they reported a smell of chlorine from their water.
A number of samples were then taken, with results coming through on Wednesday morning, and that "a small number of customers" said they were feeling unwell.
Irish Water then worked with Meath County Council to carry out a programme of flushing on the network to return the chlorine levels to the correct drinking water standards.
In a statement, the utility said: "Our investigations have indicated that an operational failure on a chlorine booster caused a very gradual over-chlorination of the water.
"This over-chlorination built gradually to the point where customers could smell the excess and told us that they were feeling unwell."
There were also reports that a number of children got sick and suffered skin rashes as a result.
Earlier, Fianna Fáil TD Thomas Byrne accused Irish Water of being too slow to react to the problem.
He said some of his constituents raised concerns "as early as Sunday and definitely Monday," adding that "certainly the smell of chlorine is there since the weekend."
"They had reported chemical burns, which arise in the form of rashes, children getting sick and going to the doctor, because of that," he said.
"In one case, an adult was reported as having got sick."