Almost 96% of group water schemes complied with E-coli standards in 2010, according to figures released today by the Central Statistics Office (CSO).
It found water quality to be generally high in Ireland, with 99.8% of public drinking water supplies compliant with E.coli standards in 2010.
The figures also show a fall in the amount of waste going to landfill, down from two million tonnes in 2007 to 1.5 million in 2010.
The CSO attributes this fall to the economic downturn.
Landfill accounted for 58% of all municipal waste that year compared with an EU average of 38%.
Meanwhile last year, 90% of all new private vehicles licensed in Ireland were in the low emissions category.
The CSO says all those factors, alongside the reduction in energy and transport use because of the economic downturn, have led to an improvement in air quality and the overall environment.