The second set of sampling results on the water supply contaminated with cryptosporidium in south and west Sligo are due today.
The HSE has been regularly testing the water after it detected the bacteria early last month.
A boil water notice had to be put in place for the 13,000 people on the Lough Talt water supply for almost a month.
Irish Water will announce the latest results supplied by the HSE today.
Deputy Eamon Scanlon says businesses have been hugely affected to date: