Over 1,400 customers will be affected.
Irish Water is putting a boil water notice in place for customers in the midlands.
The utility in consultation with the Health Service Executive, and Westmeath County Council put the notice in place with immediate effect for all customers on the Castlepollard High Level public water supply.
The Boil Water Notice affects approximately 1,444 people.
The areas affected are Ballymanus, Hilltown, Slieveboy, Loughpark, Fore, Martinstown, Glenidan, Cummerstown, Collinstown, Ranahan and surrounding areas, as shaded on the attached map.
The Boil Water Notice has been put in place as a precaution following a mechanical failure at the water treatment plant that resulted in the disinfection process being compromised.
Irish Water’s drinking water compliance and operational experts are working with colleagues in Westmeath County Council to resolve the issue as soon as possible.
In the meantime, all customers of this supply are advised to boil water before use until further notice.
Irish Water says it acknowledges the impact and inconvenience caused by the imposition of a Boil Water Notice to homes and businesses.
The utility is thanking the community for their patience and cooperation while they work to resolve this issue.
Irish Water says its priority is the provision of safe, clean drinking water and safeguarding that water supply for the future is a vital focus.