While its latest report on the quality of drinking water in the Irish public supply has found that over 99% of supplies complied with both the microbiological and chemical standards, the EPA has warned that 108 supplies are at risk.
These supplies serve 830,000 consumers.
Gerard O’Leary, Director of the EPA’s Office of Environmental Enforcement said: “So far this year, 86,000 people have had to boil their water to make it safe.
"This is more than twice as many as last year. Without investment to address the deficiencies in the supplies on the EPA’s Remedial Action List, this type of water restriction will continue to occur."
There are currently 17 supplies operating with boil-water notices.
The largest is Ballinlough/Loughlynn in County Roscommon which serves 3,500 people.
Its supply is affected by cryptosporidium.
Speaking to Morning Ireland, EPA Senior Inspector Darragh Page, said the EPA agency had taken two cases against Irish water in relation to water supplies in Letterkenny, County Donegal and An Cheathrú Rua in Galway.
Mr. Page said the Vartry-Roundwood scheme in north Wicklow/County Dublin needs a new pipeline to be constructed as it is at risk of collapse.