Kinnegad in Westmeath is among those listed as having a failure in infrastructure.
Sewage from the equivalent of 77,000 people in 36 towns and villages is released into the environment every day without treatment.
Half of the raw sewage comes from Arklow, Cobh and Kilmore Quay, according to the Environmental Protection Agency.
There are also 21 large towns and cities, including Dublin and Cork, where waste water treatment did not meet EU standards.
Kinnegad in Westmeath is among those listed as having a failure of infrastructure - with outdated facilities under-performing and occasionally breaking down in 2018.
Andy Fanning from the EPA says Irish Water needs to get on top of the issue: