Clara/Ferbane scheme listed as an 'at risk' water supply

Drinking water supply for over 7,000 people in the Clara and Ferbane areas was cited as being 'at risk' by the Environmental Protection Agency (EPA) in its Drinking Water Quality in Public Supplies Report 2023 released on Wednesday.

The Clara/Ferbane Public Water Supply scheme is included in the EPA's Remedial Action List (RAL), which identifies "at-risk" supplies that require improvements to safeguard public health.

The Clara/Ferbane scheme is included in the Remedial Action List due to what the EPA has termed elevated levels of Trihalomethane (THM) above the standard in the Drinking Water Regulations

Overall, the EPA drinking water report, shows that over 99.7 per cent of public water supplies comply with bacterial and chemical limits, which means our public water is safe to drink.

However, the EPA said many supplies still lack robust treatment measures to guarantee their long-term resilience and safety. In 2023 there was a further increase in the number of people served by supplies on the RAL (up to 561,000 – from 481,000). While it is positive to note that ten supplies were removed from the RAL following improvement works, the EPA - through enforcement and assessment activities - has identified a further nine “at-risk” supplies that were added, primarily for THM and Cryptosporidium exceedances.

The Clara/Ferbane Public Water Supply Scheme has been on the RAL since the second quarter of 2019. Uisce Éireann said an upgrade of the water treatment plant, which would result in its removal from the Remedial Action List, was scheduled to be completed by the end of June.

Uisce Éireann did not respond to a query on the matter by the time of going to press.

Launching the report, Dr Tom Ryan, EPA Director said: “Our public water quality remains very high, which means that the public can remain confident that drinking water supplied to their homes is safe to drink. However, the resilience of drinking water supplies isn’t robust enough as evidenced by more “at-risk” supplies being identified by the EPA, and an almost doubling of long-term boil water notices in 2023.”

One in twenty supplies failed to meet the THM standard in 2023 and supplies on the RAL for THMs are impacting almost 300,000 people. The EPA said greater effort is needed by Uisce Éireann to implement improvements at supplies to minimise exposure to THM’s, including at major supplies such as Limerick city, and Kilkenny city.

The report also found that 91 boil water notices and 12 water restrictions were in place in 2023.

Among the boil water notices were two in Offaly. The Birr Public Water supply scheme was subject to a boil water notice, affecting some 5,173 people, for some seven days in August/September, while the Tullamore South and Clonaslee scheme, supplying some 3,900 people, was affected for over three weeks.

What are trihalomethanes?

Trihalomethanes (THMs) form when natural organic matter in the water source, such as vegetation, reacts with chlorine used in the disinfection treatment process.

THMs are a particular issue in Ireland where about 80% of our drinking water is abstracted from rivers and lakes, with associated catchments often having peaty soil.

In relation to the health risks from THMs, HSE advice states: ‘.. [Health] guidelines for THMs are set to ensure a very low level of potential risk over a typical lifetime of consumption (i.e. 70 years). Short-term use of drinking water that exceeds guidelines is unlikely to have an impact on human health.’ It goes on to state: ‘There is insufficient scientific evidence to indicate that THMs cause cancer in people …… It should be noted that any potential health risks from disinfection by-products, including THMs, are much less than the risks from consuming water that has not been disinfected.’

However, when uncertainty exists a precautionary approach is needed and Uisce Éireann must take the necessary actions to meet the THMs limit.