The Environmental Protection Agency has warned that the new Irish Water State utility company has a lot of work to do to provide safe and secure drinking water to the public.
In its annual drinking water report, the EPA says the number of E coli occurrences in public water has reduced by 92% since 2005.
The EPA says water supplies serving more than 82% of the population have improved.
However, the report states there are still serious issues to be dealt with.
Thousands of people are still boiling water in 30 different parts of the country - almost 15,000 in Co Roscommon alone - and 140 public supplies need urgent remedial action.
The report also highlights EPA concerns about E coli cases emerging from private wells where the water has not been disinfected.