Cryptosporidium can cause serious gastrointestinal illness, particularly in young children and the elderly.

The Environmental Protection Agency (EPA) has served notice of an increase in detections of cryptosporidium in public water supplies in Ireland. According to the Drinking Water Quality in Public Supplies Report 2018 released this week, there were detections of cryptosporidium in 25 public water supplies last year, up from 17 in 2017 and 12 in 2016. Of particular concern, the EPA says, are supplies which have inadequate processes in place to treat or remove cryptosporidium and those where there is no treatment in place at all. In total, 64 water supplies are currently on the EPA’s Remedial Action List (RAL), a register of public water supplies with the most serious deficiencies, known to be most at risk and where the EPA is requiring Irish Water to take corrective action to ensure the safety and security of the supplies by set deadlines. You can see the Remedial Action List in full here, which includes the water supplies below where treatment of cryptosporidium is considered inadequate.

• Glenties-Ardara (Donegal)
• Creeslough (Donegal)
• Letterkenny (Donegal)
• Lough Talt Regional Water Supply (Sligo)
• Ballycastle (Mayo)
• Mullingar Regional (Westmeath)
• Glenmore (Kilkenny)
• Pilltown-Fiddown (Kilkenny)
• Clonmel Poulavanogue (Tipperary)
• Abbeyleix 1 PWS (Laois)
• Ballyhooly (Cork)
• Glengarriff (Cork)
• Castlecove 023H (Kerry)
• Mountain Stage 062A (Kerry)
• Croom (Limerick)

On a more positive note, the EPA report notes that the quality of drinking water in public supplies remains high, with 99.9% compliance with microbiological parameters and 99.6% compliance with chemical parameters. Commenting on the report and on the increased detection of cryptosporidium in particular, Dr Tom Ryan, Director of the EPA’s Office of Environmental Enforcement said: "We are seeing an upward trend in cryptosporidium contamination in drinking water supplies. "We know that cryptosporidium can cause serious gastrointestinal illness, particularly in young children and the elderly, and the EPA has ensured that Irish Water has investigated each of these cryptosporidium detections. "Irish Water must make certain that water treatment plants are properly and effectively operated to protect public health. Those plants without appropriate treatment for cryptosporidium need to be prioritised for investment by Irish Water.” Following 58 audits of water treatment plants and three audits of Irish Water’s monitoring programmes in 2018, the EPA has identified the following priorities for Irish Water to address on a national level to protect and improve public water supplies:

• Progressing action programmes for all Remedial Action List schemes
• Prevention of long-term boil water notices by providing robust disinfection systems
• Minimising harmful disinfection by-products such as Trihalomethanes (THM) by providing treatment that adequately removes organic matter in the water
• Eliminating lead from our drinking water networks
• Preventing pesticides from entering our drinking water sources
• Managing risks to our public water supplies by adopting Drinking Water Safety Plans for all supplies

You can read the Drinking Water Quality in Public Supplies Report 2018 in full here.