Residents of a Co Clare village were provided with unsafe drinking water for 12 months before the authorities warned the public that water from the supply should be boiled, according to the State environment watchdog.
An audit by the Environmental Protection Agency has revealed that a water treatment plant which serves a population of around 1,000 people in and around the east Clare village of O’Brien’s Bridge had distributed inadequately disinfected water for a full year before the scale of the problem was recognised.
EPA officials found "a lack of communication" between Clare County Council and Uisce Éireann (formerly Irish Water) had resulted in a significant delay in identifying the full extent of the deficiency in the ultraviolet disinfection system of the O’Brien’s Bridge supply.
A Boil Water Notice was finally issued on August 25th, 2023, for the protection of public health following consultation with the HSE – around 12 months after the supply’s UV disinfection system had been out of operation.
The EPA said the failure of Uisce Éireann to notify it and the HSE of the failure of the UV disinfection system for “a prolonged period of time” meant the assessment of the risk to public health had not commenced “in a timely manner.”
Although disinfection of the supply with chlorine remained in place while the UV disinfection system was out of service, the audit found that the final treated water from the supply had not met the minimum recommended chlorine contact time as recommended by the World Health Organisation.
“This means that the plant produced unsafe drinking water for a period of 12 months due to the loss of the Cryptosporidium treatment barrier compounded by inadequate chlorine contact time,” the EPA said.
The audit was carried out by the EPA after it was notified by Uisce Éireann about the imposition of a Boil Water Notice on the O’Brien’s Bridge supply.
It found at the time of the audit in September 2023 that the O’Brien’s Bridge water treatment plant was not capable of adequately treating raw water entering the supply because of variations in water quality following heavy rainfall.
The audit also identified a lack of control over treatment at the plant due to the absence of an online turbidity monitor which measures the level of how cloudy the water is from suspended particles in the supply.
Residents of O’Brien’s Bridge as well as other nearby villages, Bridgetown, Co Clare and Montpellier, Co Limerick, with a combined population of 944, are provided with drinking water from the supply.
Three tests carried out by Clare County Council on samples from the supply for Cryptosporidium last September were clear.
The council informed the EPA that the UV disinfection system which was installed in 2016 had frequent operational and maintenance issues which were not treated as incidents.
They included electrical faults, seal failures and no maintenance and servicing schedule being in place.
The EPA also confirmed that council staff had not received training on the UV disinfection system and were unaware of incident and response procedures.
Neither Clare County Council nor Uisce Éireann were able to confirm if the incident which first resulted in the failure of the UV disinfection system had been escalated at the time.
Uisce Éireann were also unable to state how many properties were impacted by water supplies with inadequate chlorine contact time.
The audit also claimed that the abstraction source for the O’Brien’s Bridge public water supply – an unsealed borehole – was not adequately protected against contamination.
The EPA said a lack of chlorine alarms to the supply meant staff were prevented from reacting in time when chlorine levels drop below recommended targets.
Similarly, there was no plant shutdown set for when turbidity reached a certain level to prevent inadequately treated water from entering the distribution network.
Uisce Éireann said the UV disinfection system went back into operation on September 6th, 2023, but further work was required to ensure it operated to expected standards at all times.
Recommendations
The EPA issued Uisce Éireann with a series of recommendations to implement without delay to ensure a clean and wholesome supply of drinking water was provided by the O’Brien’s Bridge treatment plant.
The Boil Water Notice was lifted by Uisce Éireann after almost two months on October 19th, 2023.
The utility said its primary focus remains the protection of public health and it had worked to lift the notice as quickly as possible.
However, no reference was made to the fact that inadequately treated water had been distributed from the plant in O’Brien’s Bridge for 12 months in four public statements issued by Uisce Éireann between August and October 2023.
