Bathing in the sea at Waterville in south Kerry will remain closed until later this week after lightning struck a pumping station at the town's waste water treatment plant.
The €18m plant opened in 2013 after a decade long campaign by locals and Waterville picked up a Green Coast award this year for the quality of its water and the overall cleanliness of its beach.
However an overflow on Sunday after lightning struck a pumping station at Village Green may have affected the bathing water quality, Irish Water said.
A bathing water notice is in place "as a precautionary measure".
Crews gave been on the ground since the strike, maintaining the pump station and there have been no overflows from the pump station since the initial and limited overflow.
A repair has been carried out and it is expected that the issue will be resolved later this week when bathing water quality testing is complete.
Nearby blue flag beaches at Ballinskelligs, Derrynane and White Strand are not affected.
