A massive €870m of taxpayers' cash, spent on upgrading water treatment plants over five years, has resulted in 'little significant improvement' in our water quality.
Despite the cash injection between 2002 and 2007, only minimum safety standards are being met in most public water supplies - and the quality of supplies to a small section of the population has actually deteriorated.
The Comptroller and Auditor General (C&AG) also states that there are ongoing problems with drinking water supplies being contaminated with E coli, cryptosporidium and other potentially dangerous bugs.
The report on expenditure in water infrastructure by the Department of the Environment found that 339 public supplies - accounting for 36pc of all supplies - need 'immediate action' to help improve drinking water quality.
EPA monitoring has found that E coli is present in 5pc of all public supplies and the C&AG says continued investment in treatment plants would lead to improvements. In addition, he says that more prosecutions are needed.
Ireland compares poorly with many of our EU neighbours in terms of safety of our drinking water. Ireland has the highest rate of cryptosporidium contamination among 16 EU nations, while levels of E coli contamination are nearly 30 times higher than found in supplies in England and Wales.
Around 1.1 million people are drinking water which may not have been properly treated.
The Department of the Environment said it recognised that further improvements were necessary, but that half a billion euro would be spent this year on new infrastructure.
"Most of the areas identified as requiring investment, are earmarked for funding or work is underway or due to commence shortly" - a spokesman said.
The Irish Independent