The warning was first issued on September 2nd
A boil water noticing affecting almost 50,000 people in Mayo has been lifted.
The warning was first issued on September 2nd, and affected households in some of Mayo's largest towns.
This including Castlebar, Claremorris and Westport.
The notice followed the discovery of cryptosporidium in a sample from the Lough Mask regional water supply scheme.
No further contaminated samples have been detected since the original incident.
The Health Service Executive (HSE) also says it has not treated any associated illnesses.
Mark McCauley is a spokesman with Irish Water.