More than 300 public water supplies could pose a threat to public health because they have not been properly assessed or are not following proper procedures.
The claim is made in a report on Ireland's drinking water published this morning by the Environmental Protection Agency.
The report says that in 2006, 8% of public water supplies showed at least one incident of E. coli contamination.
Speaking on RTÉ Radio's Morning Ireland, Dara Lynott, director of the EPA office of environmental enforcement, said the level of contamination is unacceptable.
'If you look at what this report is saying, it's saying that the level of contamination of public water supplies is not up to European standard, Mr Lynott said.
'It's not acceptable given that the E. coli standard in Europe is zero.'
The agency says the problem is in both public and private supplies. In 2006 more than third of private group supplies showed some level of E. coli contamination.
It says things have improved and continue to get better but procedures remain inadequate in some areas.
Today's report points out that more than 90% of water samples taken from taps in Galway during the cryptosporidium crisis were safe although cryptosporidium was in the supply at dangerous levels.
Programme manager Gerard O'Leary says that any water supply must be profiled and monitored at every stage from when it is collected until it reaches the tap.
Click the map to see the public water supplies were contaminated with E. coli more than once between 2004 and 2006.
The full report is available here
(Source: EPA)
