A total of 561,000 residents in Ireland were served by “at risk” public water supplies in 2023, up from 481,000 in 2022, according to a new report by the Environmental Protection Agency (EPA).
The EPA research shows that the deterioration in supplies was primarily due to detections of persistent levels of toxic trihalomethanes (THMs) and the parasite cryptosporidium, which causes diarrhoea and gastrointestinal symptoms.
While “the quality of drinking water from public supplies remains very high, with over 99.7 per cent of samples compliant with bacterial and chemical limits,” the EPA underlined that the resilience of supplies must improve and will require sustained investment into the future.
The report warned that too many supplies still lack robust treatment measures to guarantee their long-term safety.
While there is insufficient scientific evidence to indicate that THMs can cause cancer in people, the Health Service Executive (HSE), citing the World Health Organisation, said some of the THMs are classified as possibly carcinogenic to humans. Exposure to THM levels above the WHO guideline value could increase the risk of certain cancers such as bladder, colon and rectal.
The agency also warned that “greater effort is needed by Uisce Eireann to implement improvements at supplies to minimise exposure to THMs, including at big supplies such as Limerick city, and Kilkenny city.”
In January this year, the EU Court of Justice ruled the concentration of the chemical compound THMs in drinking water in a large number of public water supplies in Ireland had exceeded recommended safety limits since 2012.
The report also pointed out that the number of boil water notices in place for more than 30 days stood at 46, up from 25 in 2022.