Householders in Navan have been advised to boil tap water before using it to drink, wash, bathe or prepare food following the discovery of traces of contamination in the public water supply.
A spokeswoman for the council would not confirm whether it was traces of the potentially harmful bacteria e-coli which were discovered by environmental health officers.
Some 25,000 people are affected by the public warning issued on Thursday night, which put Navan and surrounding areas on a "boil alert". The contamination was detected after routine testing by the Eastern Regional Heath Authority at two locations, a petrol filling station and a private house. The health board is currently carrying out their own tests, the results of which will be known tomorrow.
The council have advised the public to continue boiling water for at least 10 minutes before using it for any purpose.
There have been ongoing problems with the public water supply. Last week the council confirmed that multiple pipe bursts in the area were due to asbestos cement pipework, which is "notoriously brittle" and was laid in the 1970s. Phase one of a replace programme is currently under way.