A boil water notice has been issued to almost 6,500 homes and businesses in Westport, Co. Mayo, following an increase in the number of people presenting with symptoms of cryptosporidiosis in recent days.
The notice, which came into effect this evening, affects thousands of homes and hundreds of businesses in the town.
Residents are being told to boil tap water if they intend to drink it, prepare food, brush teeth, make ice or infant feeds.
Irish Water says continual testing of the Westport supply in recent weeks has not revealed the presence of cryptosporidium.
It has carried out tests at the Knappable source, which supplies much of the town's water, and says all samples so far have tested negative for cryptosporidium.
