More problems have been discovered in the Co Galway water supply, with thousands of people being advised to boil all drinking water.
A contamination alert has been placed on supplies in the south of the county following the detection of a bacterium which causes gastrointestinal illness.
The clostridium perfringens organism is an indicator for the presence of the cryptosporidium parasite, which caused major problems in Galway city and surrounding areas last year.
Around 90,000 people had to boil their water for several months as a result of that contamination.