Irish Water crews are responding to a pump failure at the Ringsend wastewater treatment plant in Dublin.
A spokesman for the utility company said the incident, which he described as “low level”, was being worked on at night time when flows into the plant are lighter.
Irish Water said there is “an increased risk of storm water overflows occuring during the coming days while repairs are underway”.
The spokesman said that the risk of an incident would “exponentially increase” if there was a heavy downpour, but added that no heavy rain has been forecast in the coming days for the region.
Currently, the utility believes any overflows which occur under current conditions will be “at a small level”.
"Crews are on site working to carry out essential repairs to the pumps as quickly as possible in order to allow the plant to return to its full treatment capacity. Irish Water have notified the Environmental Protection Agency, Dublin City Council and Dún Laoghaire-Rathdown County Council of this incident," the spokesman said.
A number of bathing bans were implemented during the summer and autumn following overflows of wastewater at water treatment facilities and pumping stations including Ringsend.
The overflow of sewer debris following heavy rain threatened the 100th running of the Liffey Swim but the race ultimately proceeded without incident, despite warnings over the water quality from the HSE.
Two boil water notices had to be issued for the greater Dublin area in recent weeks following mechanical issues which led to water clouding and an increased risk of contamination at the Irish Water treatment plant in Leixlip.
That plant treats water for an estimated 600,000 people, all of whom were put on boil water notices for days at a time following the faults. The EPA has said it remains concerned, following an audit, about the ability of Leixlip water treatment plant to maintain and sustain an appropriate level of performance.
