Boil water notices have been issued for 9,865 customers in Offaly.
They have been issued by Irish Water and Offaly County Council, following advice from the Health Service Executive (HSE).
The warnings, for precautionary reasons, have been issued for the Banagher Public Water Supply, the Birr Public Water Supply and the Dunkerrin Public Water Supply.
This is due to detection of E.coli and Total Coliforms following routine water quality sampling.
Irish Water parent firm Ervia says: "In the interest of public health, all users fed from the three public water supplies must boil their water supply before use."
It says further samples will be taken and an update on the results will be provided before the weekend.
"In the interest of public health, all users fed from the three public water supplies must boil their water supply before use."
Irish Water says it is working with Offaly County Council and the HSE to ensure that a safe and compliant supply of water is returned as soon as possible.
Irish Water is also directly contacting people on these schemes who have registered as vulnerable customers.
The water must be boiled for:
- Drinking
- Drinks made with water
- Preparation of salads and similar foods, which are not cooked prior to eating
- Brushing of teeth
- Making of ice
- Discard ice cubes in fridges and freezers and filtered water in fridges - make ice from cooled boiled water