Dublin City Council has said it is looking "very positive" that restrictions on the city's water supply will be lifted on Thursday morning.
Dublin City Council engineer Michael Phillips said two-thirds of lost production had been recovered and the reservoirs were again filling up with treated water supplies.
Speaking on RTÉ's Morning Ireland, Mr Phillips said: "If we can get it to full production and it stabilises, which we should know by Thursday morning, then we will consider lifting the restrictions at that stage."
He said it would take a number of weeks to analyse all the chemical data in a "really detailed manner" to minimise the chances of the same situation arising in the future.
Mr Phillips said climate change had affected the chemical makeup of the rain that was falling into lakes.
He said: "There could be slight changes in the characteristics of the rivers that we don't fully understand at present.
"It's only over periods of time, because climate change is a very slow process, as we gather data that people will suddenly see a trend."