"The fact remains that technically [and legally] significant numbers of drinking waters are still bacteriologically unfit for human consumption," concludes the Environmental Protection Agency's most recent evaluation of Irish drinking water.
This relates to 1998, the latest year for which results are available. Many thousands of samples are checked annually from every local authority and hundreds of group water supply schemes serving about a fifth of households, mostly in rural areas.
There is always a lag in conclusions because of the time this process takes. Yet the same conclusion as on the 1998 samples could have been reached every year back to 1985, when the EU drinking water directive first came into force.
So what is the up-to-date picture?
Some 42 per cent of group water schemes serving a vast hinterland of rural Ireland were contaminated; 80 per cent of these contained faecal bacteria, indicated by the presence of coliforms such as E.Coli. While not E.Coli O157 (the most serious form), it indicates contamination by sewage or livestock waste, such as slurry. It constitutes a significant health risk.
Some 8 per cent of public supplies were unacceptable based on bacterial contamination (half of which had faecal bacteria), a further 5 per cent had odour problems and 3 per cent had taste problems. The latter two categories are more of a nuisance.
In group schemes, over-chlorination causes most taste problems. In many rural areas, however, chlorination (or effective disinfection) is not carried out or is "wholly ineffective".
The latest analysis is worrying, say Friends of the Irish Environment (FIE), not only because of continuing contamination in group supplies but also the extent of problems with local authority supplies (larger public sources). This despite much investment in supply infrastructure and waste-water treatment.
"Counties Sligo, Kerry, Wexford, Wicklow, Longford and Tipperary (North Riding) all reported more contaminated water supplies than ever before. Non-compliance in the Tipperary case more than doubled from 40 in 1997 to 81 in 1988," according to FIE spokesman Mr Tony Lowes. It's a story repeated in pockets of almost every county.
EPA chemist Dr Paddy Flanagan, who analyses the figures, says water from the cold kitchen tap served by the vast majority of public supplies is as good as bottled water. However, he would not drink water from a group supply until he knew its history. "In the course of a few years that [problem] will be whipped into shape but it's going to take some time."
He says the poor state of so many rural supplies relates to group schemes being "community schemes", run with the best intentions voluntarily and administered by consumers themselves.
Schemes set up in the 1960s using well water seemed to operate with no problems. Often, where water was pristine, there was no treatment. Then came agricultural intensification, storage of farm waste in small areas and spillages. These, together with the expansion of rural housing with ill-advised septic tank locations, culminated almost unknowingly in source deterioration.
He believes EPA reports help concentrate minds. Given the measures introduced by the Department of the Environment, the extent of funding committed to the problem and the professionalism of the National Federation of Group Water Schemes, "root and branch change" is happening. "I would be much more optimistic than I would have been three years ago."
Dr Flanagan admits the extent of non-compliance with EU standards on coliform bacteria is high in the European context, though comparison with the rest of the EU is not always appropriate. Europe has had to deal with the consequences of heavy industry rather than bacterial contamination. Ireland has avoided such threats. However, according to Mr Tony Waldron, of the Corrib Catchment Water Protection Group, further recent deterioration in lakes and rivers indicates it is no longer a quality issue a move to less than pristine water with obvious impact on angling but a serious public health problem.
Lough Mask, which last year showed small but worrying accumulations of potentially toxic algal blooms and was downgraded by the EPA in terms of classifying its water status, supplies drinking water to Castlebar and other Co Mayo towns. A similar risk arises with Lough Corrib, which supplies Galway city and other towns. Such a scenario exists in every region.
This deterioration, says Mr Waldron, is due to phosphate control regulations not being binding and the failure of local authorities to implement laws to control agricultural discharges.