Hundreds of households around the Dunkerrin area on the Tipperary border have been hit by a boil water notice.
Irish Water issued the notice after low levels of E.coli were found in the local water supplies covering an area as far as Birr and Banagher.
Just under 10,000 households are affected in total and it thought the notice may stay in effect until early next week.
Dunkerrin is on the Nenagh to Roscrea road in an area of Offaly that dips into the Premier County around Moneygall. It is 14kms from Templemore and less that 8kms from Roscrea.
In a statement on its website, Irish Water says that following the advice of the Health Service Executive, Irish Water and Offaly County Council, have issued boil water notices for precautionary reasons on Banagher public water supply, Birr public water supply and Dunkerrin public water supply.
This is due to detection of E.coli and Total Coliforms following routine water quality sampling.
In the interest of public health, all users fed from the three public water supplies must boil their water supply before use. Further samples will be taken this Friday, July 14, 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 is directly contacting those individuals on these schemes who have registered as vulnerable customers. Details of the notice are available on the services and supply section of the Irish Water website and future updates will also be posted to this section.
As Dunkerrin straddles the Tipperary border, it is not clear if any households in Tipperary are affected by the outbreak.
Irish Water has issued the following notice to cope with the situation and to inform households what water must be boiled for:
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.
What actions should be taken:
Use water prepared for drinking when preparing foods that will not be cooked (e.g. washing salads).
Water can be used for personal hygiene, bathing and flushing of toilets but not for brushing teeth or gargling.
Boil water by bringing to a vigorous, rolling boil (e.g. with an automatic kettle) and allow to cool. Cover and store in a refrigerator or cold place
Water from the hot tap is not safe to drink. Domestic water filters will not render water safe to drink.
Caution should be taken when bathing children to ensure that they do not swallow the bathing water.
Prepare infant feeds with water that has been brought to the boil once and cooled. Do not use water that has been re-boiled several times.
If bottled water is used for the preparation of infant feeds it should be boiled once and cooled. If you are using bottled water for preparing baby food, be aware that some natural mineral water may have high sodium content.
The legal limit for sodium in drinking water is 200mg per litre. Check the label on the bottled water to make sure the sodium or `Na' is not greater than 200mg per litre. If it is, then it is advisable to use a different type of bottled water.
If no other water is available, then use this water for as short a time as possible.
It is important to keep babies hydrated.