Environment Minister Phil Hogan said that he is hopeful that water restrictions in the Greater Dublin Area can be lifted later this week.
Minister Hogan has also revealed that the problem was with the addition of chemicals to the water at intake at the Ballymore Eustace plant in Co Kildare.
Production at the facility is now improving, though not enough to lift the night-time restrictions yet.
"The chemicals being deployed to the characteristic of the water supply at intake weren't exactly sufficient to deal with the particular purities that would be normally in the water," he said.
"When it goes from sedimentation tanks to filtration tanks there was still some doubt about the quality of the water, so there had to be restrictions made in order to ensure that the high quality and good quality water supply to the people in region, particularly Dublin, was maintained."