Over 100 public drinking water supplies are at risk according to Government experts.

The Environmental Protection Agency says the tap water for 830-thousand people needs work to make it safe.

There are concerns that in some cases not enough is being done to prevent the parasite Cryptosporidium from entering the supply.

Cryptosporidium causes stomach bugs and breathing problems.

However the EPA has confirmed that the majority of our 962 drinking water supplies are safe and comply with microbiological and chemical standards.

The report shows that boil notices were in place on 20 supplies in 2015 as a result of detections of E coli and cryptosporidium, 12 of which were issued prior to 2015 and remained in place during 2015 and 8 of which were newly issued in 2015.

On the long term boil notices in place in 2015, 7 were lifted, 5 of those in Co Roscommon, benefitting a population of 17,243 people. A precautionary boil notice was also lifted in Co Roscommon in 2015 benefitting 3,443 people.

Two separate water restrictions were issued to a housing estate on the Galway City Council public water supply as a result of hydrocarbon contamination. The EPA issued a regulation on December 1^st last year, directing Irish Water to put measures in place to prevent a further incident and the utility installed return valves on each individual premise and is currently replacing the mains within the estate and works are due to be completed by the end of this year.

THMs are disinfection by-products that can form where the organic matter in the raw water reacts with chlorine. These compounds are undesirable in drinking water and the EPA has complied a Remedial Action List which highlights the supplies in need of improvement and that pose a risk to consumers. Three of those supplies are in Mayo, with a similar number in Roscommon and Sligo, while there are 7 in Galway and one in Leitrim.

The majority of an EPA audit is dedicated to a detailed, critical appraisal of the treatment process. Of the 69 audits completed in 2015, 5 supplies, including Spiddal in Galway, were found to be operating above 110% of its design capacity.

The EPA issued 31 legally binding Directions to Irish Water during 2015. They included the Swinford supply in Mayo for failure to respond to EPA requests, Leenane in Galway for no cryptosporidium barrier and no out of hours response procedure, however an action programme has been submitted but more specific direction issued by the EPA as insufficient detail was provided, Inishmore Cregacareen in Galway for having no action programme and THM exceedances and Galway City for an inadequate reponse to an EPA audit report.