Irish Water says one of the broken down pumps at the Ringsend Wastewater Treatment plant is scheduled to be operating again by tomorrow morning.
The utility issued a warning yesterday that there may be overflows of semi-treated waste into Dublin Bay while repairs were under way.
Residents in the Ringsend and Irishtown areas have complained of foul odours from the plant in recent days and say this is a common occurrence during easterly winds.
The plant also suffered a mechanical breakdown last February and there also overflows during the summer.
The Environmental Protection Agency has said that the plant is non-compliant with EU law as it is operating at 20% over capacity.
The plant will be upgraded at a cost of €400 million by 2023 and Irish Water recently received planning permission for a new plant at Clonshaugh in north Dublin.