Councillors in the north Dublin town of Swords have expressed hope that a water alert over the E-coli bug will end in the next few days.
Households in the Knocksedan estate have been warned to boil drinking water after the discovery of the bacteria.
The precaution, first issued on August 8th, remains in place until the source of the contamination is identified.
Fingal councillor Joe Corr of the Green Party said he is confident that households affected by the discovery of E. coli in their water supplies "will soon have clean water flowing through their taps again".
"I have spoken to the relevant authorities within Fingal County Council and I am confident that they are doing everything they can to swiftly restore clean water supplies to the Knocksedan Estate," Mr Corr said.
He said he understood a water mains pipe was breached last week and that the supply had been contaminated - probably from an agricultural source.
"That breach has been isolated and repaired, and the Council is now conducting tests to ensure that the water supply is back to normal," he said.
"There have been daily tests carried out. The test on Monday was clear and the council is currently awaiting the results of yesterday's test."
Fingal County Council said yesterday the contamination occurred within about 1 km of the estate and does not effect the whole Swords area.
"We are continuing to do everything to identify the exact source of contamination so that normal water supply can be restored as soon as possible," said a spokeswoman.
"It is a possibility that the source of the contamination cannot be determined conclusively, but the ouncil is carrying out all necessary measures to eradicate the contamination.
"Until such time as an all clear notice is delivered to each house the boil water notice remains in effect."
A 70-year-old Scottish woman was hospitalised in Ireland in recent days suffering from E-coli poisoning but the Department of Health says there are no concerns about an outbreak of the potentially fatal bug in Ireland.