The water supply to a housing estate in north Dublin is contaminated with E.coli, it was confirmed tonight.
Residents in the north Dublin development have been warned to boil drinking water after the discovery of the bacteria in the system.
The precaution, first issued on August 8th, remains in place until the source of the contamination is identified.
Council chiefs stress there is no immediate danger to householders in Knocksedan Estate, Swords.
Fingal County Council said 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 Council 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."
Possibilities given for the cause include a leak in the supply main which is allowing contaminated surface water to get into the watermain when pressures are low or someone opening a fire hydrant to "take" water but contaminated surface water was allowed to enter the system as a result.
A consumer could have also contaminated his/her water supply which then was accidentally backfed (sucked) into the Council main, contaminating the water, the council said.
Meanwhile, boiling water notices have been lifted in Glenbeigh, Co Kerry, where the water supply last week tested positive for E.coli.
Latest figures from Ireland's Environmental Protection Agency show 98.9 per cent of public water supplies comply with e.coli standards compared to 77.5 per cent of private supplies.
According to the EPA's 2005 water quality report 36% of private water schemes were contaminated with E. coli at least once during that year.
It was also confirmed today that a 70-year-old Scottish woman has been hospitalised in Ireland suffering E-coli but the Department of Health says there are no concerns about an outbreak of the potentially fatal bug in Ireland.
A Department of Health spokeswoman said she understood the woman was on holiday on Ireland when she was struck with the illness which has at least a two week incubation period.
She stressed there was no concern about an outbreak in Ireland.
A woman has died and two more people are seriously ill after an outbreak of E.coli in Scotland which may have been caused by cooked meat from the supermarket chain Morrison, health authorities said today.
PA
Additional reporting: Reuters