Uisce Éireann has issued a Boil Water Notice for customers in the Castlerea area following a mechanical issue at a local plant.
The national water utility has confirmed 4,400 customers across Castlerea town, Ballintuber, Castleplunket, Kilmurray and surrounding areas, are impacted.
The area is served by the Castlerea Regional Water Supply Scheme.
Drinking water experts from Uisce Éireann are working to rectify the issues at the treatment plant.
In the meantime, all customers on this supply are advised to boil water before use until further notice.