It's been in place June 20th, and over 2,000 premises are being impacted.
Uisce Éireann says it's still working to lift a boil water notice in the midlands.
The warning was first issued on Tuesday, June 20th, and is affecting customers in the Tullamore South area and Clonaslee.
Over 2,000 premises are being impacted.
Drinking water experts are working to implement solutions to lift the notice as quickly as possible in consultation with the HSE.
Uisce Éireann advises that all customers on the Tullamore South and Clonaslee Water Supply including Spollanstown, Charleville Road, Clonminch, Clonaslee Village, Castlecuffe, and surrounding areas should continue to boil their water until further notice.
John Gavin, Regional Asset Operations Lead at Uisce Éireann, says:
"In conjunction with Offaly County Council, we are continuing to improve the water treatment processes at the treatment plant. Once these improvements have been completed, and the plant is fully operational, we will undertake sampling, monitoring the performance of the plant with a move towards lifting the Boil Water Notice, in consultation with the HSE. Please be assured we are working to resolve the issue and lift the notice as quickly as possible.
Public health remains our number one priority and we appreciate the impact that this notice is having on our customers in the area."
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