The Mullingar Water Supply at Portloman has been added to a "watch list" for inadequate barriers to Cryptosporidium.
The Portloman Water Treatment Plant supplies water to a population of almost 50,000 people in Mullingar and surrounding areas.
Irish Water have stated however that the drinking water "is safe to drink".
Cryptosporidium is an infection caused by tiny, one-celled cryptosporidium parasites.
In most healthy people, a cryptosporidium infection produces a bout of watery diarrhea and the infection usually goes away within a week or two. If you have a compromised immune system, a cryptosporidium infection can become life-threatening without proper treatment.
Symptoms may include watery diarrhea; dehydration; lack of appetite; weight loss; stomach cramps or pain; fever; nausea; vomiting. These symptoms may last for up to two weeks, though they may come and go sporadically for up to a month.
In a statement, Irish Water say the Environmental Protection Agency’s (EPA) Remedial Action List (RAL) is a list of all the public water supplies that are in need investment and have an approved action plan.
"Irish Water can confirm that the Mullingar Water Supply (Portloman) has been added to the EPA’s RAL due to a risk to the supply associated with inadequate barrier for Cryptosporidium.
"Irish Water is reviewing the options available to remove this risk.
"An action plan will be submitted to the Environmental Protection Agency for approval.
"Once approved, Irish Water will then write to all users of this public water scheme to inform them further on this issue, the actions that will be taken to remove the risk and by when it is expected these actions will be completed.
"The Portloman Water Treatment Plant supplies water to a population of almost 50,000 people in Mullingar and surrounding areas.
"The drinking water being supplied from Portloman Water Treatment plant is safe to drink.
"It is regularly tested like all public water supplies against a range of standards set out in the European Drinking Water Regulations. These standards are based on guidelines prepared by the World Health Organisation (WHO).
"If an immediate risk to the public health were to arise from drinking this water members of the public would be informed immediately."
Speaking about the RAL and the ongoing work, Irish Water’s Regional Compliance Specialist Andrew Boylan said:
“The publication of the latest RAL confirms that whilst improvements have been made the scale of the challenge faced by Irish Water in ensuring the delivery of clean and wholesome water in the county is significant.
“As a single utility Irish Water is able to conduct a comprehensive evaluation of the performance of Ireland’s drinking water production plants and where serious compliance challenges are found they can be tackled more effectively and efficiently,” he added.
“Nationally Irish Water has adopted a prioritised programme of works which will require an investment of €2 billion by 2021. Significant improvements are being achieved year on year by this approach right across the country.”