The second set of sampling results on the Lough Talt water supply contaminated with cryptosporidium are due this evening.
The HSE has been regularly testing the water after it detected the bacteria early last month.
A boil water notice has been put in place for the 13,000 people on the Lough Talt water supply for almost a month now. It is impacting on consumers in south and west Sligo/ and areas of east Mayo,
Irish Water will announce the latest results this evening. Representatives of the water utility company are due to meet the HSE about 4pm to evaluate the results supplied by the latest testing.