The Environmental Protection Agency (EPA) has said that up to 700,000 consumers in Ireland are at risk of drinking contaminated water, with 161,000 at risk of developing a "crippling illness" from microscopic parasites in the water.
The EPA says that areas affected include Letterkenny, Donegal, Killarney and Tralee in Kerry, Portlaoise, and parts of Sligo.
Other areas at risk of bugs include Millstreet, Co Cork; Creeslough and Glenties-Ardara in Co Donegal; Kenmare, Co Kerry; the Bennettsbridge supply in Co Kilkenny; parts of Carrick-on-Suir; the area of Clonmel-Poulavanogue, and parts of Roscommon.
In total, The Irish Independent reports that the EPA estimate more than 700,000 Irish consumers are consuming water that is needed to be treated.
E.Coli has been increasingly found in water samples, and that it's believed to be from pesticides dumped in water supplies.