The Environment Minister has admitted there are concerns about the quality of Dublin's drinking water.
Supply has been restricted for the past week, but the City Council denies there are any health risks.
Production at a water treatment plant is now improving, but night-time supply will be limited until at least Thursday.
Phil Hogan says chemicals being used to treat the water "weren't exactly sufficient to deal with the particular impurities that would be normally in the water".
The Minister admitted "there was still some doubt about the quality of the water".
Engineers say storage levels at Ballymore Eustace in Kildare are still at an 'unsustainably low level'.
A Dublin City Engineer said “since we identified the problem, we deployed all available resources, and continue to do so, 24 hours a day, to remedy the problem of loss in production at the Plant".
Michael Phillips says they have made "significant progress in turning around the difficult situation at the Treatment Works, so that the production of water has begun to improve".
Homes and businesses are being asked to continue to use as little water as possible, when they supply does return to normal.
