Laboratory test have confirmed that water supplies in Galway city and a large part of the county have been contaminated and are linked to a sharp increase in the number of people affected by a gastro-intestinal illness.
The latest figures show that 60 people have now contracted the illness, known as crypto-sporidiosis.
The Health Service Executive is urging people to boil tap water.
Galway County Council believes that the contamination is coming from animal sources.
