Two years ago the Environmental Protection Agency (EPA), which only last month was given the power to enforce standards in water quality in local authority plants, attempted to assess the potential problem cryptosporidium posed and asked every council in the country to carry out risk assessments on its public water supplies.
Only two-thirds of councils complied with this request.
However, of the councils which responded, it emerged that 21 per cent of the water supplies covered were either at "high risk" or "very high risk" of contamination from cryptosporidium, as the water was not properly filtered and was coming from lakes or water bodies at risk of contamination.
The EPA survey results in 2005 identified a number of regions at particular risk, although in the interim some of the water plants may have been upgraded. These included most of Co Longford and Co Galway, large parts of Co Donegal and Co Leitrim, and parts of counties Kilkenny, Laois, Carlow and Kerry. The EPA has sought updated information from every county.
The figures do not relate to small local group schemes. Anybody concerned about their water supply should contact their local authority, which should be able to provide details about the status of the specific supply concerned.