The European Commission has warned Ireland that it faces legal action unless it takes steps to ensure that drinking water supplies to almost 300,000 people are clean.
Officials in Brussels have urged authorities here to take any measures necessary to ensure that water supplies are fit for human consumption and to take remedial action as soon as possible to improve the quality of drinking water.
The European Commission said Ireland has not been complying with rules on drinking water since December 2003, despite making some progress over the intervening years.
Its warning comes over claims the State has failed to fulfil its obligations under the Drinking Water Directive in relation to Trihalomethane (THM) levels in public water schemes.
THMs are compounds including chloroform which occur in drinking water as a result of reaction between organic materials such as soil and rotting vegetation and chlorine which has been added as a disinfectant.
High THM levels have been linked to diseases of the liver, kidney and central nervous system as well as bladder and colon cancer. Studies show THMs can also affect foetal growth, foetal viability and risks of foetal malformations.
The European Commission has now issued the Irish authorities with a reasoned opinion which allows them four months to remedy the situation.
“Should Ireland fail to take appropriate action, the Commission may decide to refer the case to the Court of Justice of the European Union,” it said.
The possibility of a legal action at the Luxembourg-based court raises the prospect of the Government being hit with large daily fines until it achieves compliance with EU legislation.
The Environmental Protection Agency said the problem of high THM levels in Ireland was due to the fact that most drinking water comes from surface water such as rivers and lakes which have more natural organic matter than groundwater.
The latest figures show that Irish Water notified the EPA of 54 supplies across 18 counties that failed the THM standard at least once during 2018. It represented a decrease from 90 supplies in 2016.
However, around 300,000 people are still affected by drinking water supplies that are on the EPA’s remedial action list for persistent THM issues.
Irish Water has indicated that all THM action plans will be completed in all supplies by 2021.
According to the HSE, some medical studies suggest a link between long-term exposure to THMs and cancer and reproductive effects but the evidence is not conclusive. There is some evidence to suggest THMs cause cancer in animals.
However, both the HSE and Irish Water stress that any possible risks from THMs are much lower than the risk of serious illness that could result from drinking water that has not been properly disinfected.
The Department of Housing, Planning and Local Government said Ireland had been making progress on the complaints raised by the Commission.
A spokesperson pointed out the original complaints cited 97 drinking water schemes but the figure had now reduced to 44.
The spokesperson said official were examining the reasoned opinion and would together with other stakeholders provide a comprehensive response to Brussels on further progress and an updated programme of works to address any remaining issues.
Last week, Irish Water appealed with people to conserve water following a significant upsurge in usage since the imposition of Covid-19 restrictions.
Domestic metering data shows households are using an extra 24 litres of water per person per day, a 20% rise from February.