Almost 90 public drinking supplies serving more than 700,000 people have been classified as “at risk” of threatening human health.
Counties Kerry, Cork and Donegal account for almost half of the 87 "at risk" supplies identified by the Environmental Protection Agency (EPA) in a water quality review published on Tuesday.
These are categorised as most in need of improvement based on a threat to human health or likelihood of chemical contamination.
The EPA Drinking Water Report for 2016 also states that action programme dates set out by Irish Water to improve 24 "at risk" supplies have slipped.
The EPA identifies 32 supplies at the end of 2016 serving more than 163,000 people in need of adequate treatment to prevent cryptosporidium occurring in water. It is a microscopic parasite that often causes severe gastrointestinal illness when it gets into supplies, though it is easy to remove in water treatment works by use of filters and, in some instances, ultra-violet light.
The report also highlights high levels of disinfection by-products in supplies; persistent pesticide failures in some supplies, and a continuing incidence of lead pipe connections in public networks and private houses.
The agency issued 41 “boil water notices” during 2016, affecting supplies for more than 84,000 people.
Remedial action undertaken by Irish Water, which is responsible for providing and developing public water services, reduced the areas where notices were required to 10 supplies by the end of the year, affecting 5,654 people.
Water consumption
The report says “the overall quality of drinking water in public supplies remains high though further improvements are necessary to improve the security of supplies” and to avoid restrictions on water consumption.
Drinking water testing throughout 2016 confirmed a very high level of compliance with microbiological (99.9 per cent) and chemical standards (99.5 per cent), indicating the majority of water supplies are safe. Only three supplies were found to contain E. coli bacteria which can cause debilitating illness.
The report sets out key priorities for Irish Water. These include minimising the harmful disinfection by-product known as Trihalomethane (THM) arising in water by providing treatment that adequately removes organic matter in water.
It says the utility should ensure the elimination of long-term boil notices “by providing robust disinfection systems”.
The EPA also seeks the implementation of a national plan to eliminate pesticides in drinking water, as well as the elimination of lead piping in water networks.
Irish Water should be managing risks to all 904 public water supplies serving 1.3 million households by adopting “drinking water safety plans” in each case, it says. Such an approach “identifies problems before they become a risk”, explained the EPA’s senior drinking water inspector Darragh Page.
Microbiological standards
Irish public water supplies were among the best in Europe in meeting microbiological standards but below the EU average for chemical standards, notably THM, he said.
A total of 15 “directions” were issued to Irish Water by the EPA in 2016. These arise where the agency is notified of a water quality failure but is unhappy with the investigation of the cause, or with actions being taken. In such cases the agency sets out what needs to be done.
Gerard O’Leary, director of the EPA’s office of environmental enforcement, welcomed the overall improvement in water supplies but confirmed boil water notices were still in force in areas across nine counties.
“While the removal of long-term boil water notices in supplies like the Whitegate regional supply in Cork and Loughrea public water supply in Galway in 2016 was welcome, there remains over 3,600 people on a boil water notice today.”
The EPA's "remedial action lists" are available at epa.ie/pubs/reports/water/drinking/
