The Boil Water Notice for customers supplied by the Lanesboro Public Water Supply Scheme in Longford has been lifted with immediate effect.
The notice was imposed two weeks ago on the 2nd of this month after a failure with the mechanical disinfection process at the plant in Lanesboro.
It affected almost 5,000 households and businesses.
While the mechanical issue was fixed in a matter of days, Irish Water had to wait for a number of water samples to be given the all-clear by the HSE.
Irish Water says the water is now safe to drink again, but any customers who have queries about the notice and the lifting of it can contact the customer care helpline on 1850 278 278.