Unreported problem at Clare water treatment plant left people at risk of illness for weeks, EPA finds

The disabling of the UV alarm had resulted in the failure of the plant’s cryptosporidium barrier which prevents a potentially dangerous microscopic parasite that can cause gastroenteritis from entering the supply

Mon, 04 May, 2026 - 12:51

Sean McCarthaigh

Consumers were placed at potential risk when a problem at a water treatment plant in Co Clare went unreported for six weeks, according to a report by the Environmental Protection Agency.

An EPA audit revealed an automatic shutdown of the water treatment plant at O’Brien’s Bridge failed to work when turbidity level spiked in excess of recommended limits over a three-week period.

It found the turbidity alarm at the plant did not activate because it had been disabled when high turbidity levels were recorded between December 30, 2025, and January 19, 2026.

Turbidity is a measure of the cloudiness of water caused by suspended particles.

The audit also revealed that the ultraviolet disinfection system at the plant was not operating properly on January 15 to 18 but an automatic shutdown was not activated as the UV alarm was also disabled.

The report noted that the incidents were not reported by Uisce Éireann to either the HSE or the EPA with the EPA only first being notified on February 12.

“The failure by Uisce Éireann to report these incidents prevented the HSE in determining the potential risk to consumer health on the O’Brien’s Bridge supply, and also prevented any timely actions, alarms and appropriate operational controls,” it added.

The plant provides drinking water to a population of just under 1,000 in Montpelier, Co Limerick, and Bridgetown and O’Brien’s Bridge in Co Clare.

The EPA acknowledged that the plant was operating normally on the day of the audit last February with turbidity levels within recommended limits.

Uisce Éireann claimed it only became aware of elevated turbidity levels in the supply when gathering data for an EPA audit. It said the alarms at the plant had been disabled at the end of December 2025 without prior approval or communication with Uisce Éireann.

The audit noted that the disabling of the UV alarm had resulted in the failure of the plant’s cryptosporidium barrier which prevents a potentially dangerous microscopic parasite that can cause gastroenteritis from entering the supply.

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The EPA said it was confirmed that the operators of the plant at O’Brien’s Bridge had received incident awareness and response training but training and procedures had not been followed.

Uisce Éireann admitted that the exact reasons for the spikes in turbidity was unknown, although it believed it might be linked to an increased pumping rate.

The EPA said that might indicate that the borehole used to source drinking water was being pumped “above a safe yield to meet demand".

“The treatment processes on-site are unable to cope responsively to raw water changes when demand increases,” the audit observed.

EPA recommendations

Uisce Éireann said it was investigating a number of possible corrective actions to address the turbidity issues including looking at alterations to the borehole pump operating regime.

The company informed the EPA that nearby houses served by the plant have septic tanks which are likely to be within the areas from which the drinking water supply is sourced.

The EPA recommended that Uisce Éireann liaise with Clare County Council to ensure inspections are carried out on the septic tanks to assess if they are operating optimally and not presenting a risk to human health or the environment.

It also called for the borehole to be adequately capped and sealed.

The EPA asked Uisce Éireann to provide it with a report on the actions taken and planned with timescales on eight recommendations contained in the audit.