A Do Not Consume water notice has been issued for Belturbet.
Irish Water says that due to increased levels of manganese, users of the Belturbet Public Water Supply scheme in Cavan are being told to not use the water for drinking or food preparation.
The notice applies to the almost 2,000 customers of the scheme and doesn't impact any other local schemes.
Irish Water is advising that boiling the water will not make it safe to consume, and tankered water is available from Centra Belturbet or the Lawns in the town.
Tankered water should be boiled before use as a precaution.