Treatment plant at centre of crippling boil water notice had previous scare

Details of the incident which occurred last March emerged as the company announced the boil water notice currently affecting 600,000 people served by the plant was to continue for another night.

Irish Water will meet the Environmental Protection Agency (EPA), the HSE and Fingal County Council today to decide if it is safe to lift the notice which has been in place since Tuesday.

Details of the March incident are contained in an EPA audit report which concluded it "presented a significant risk to the safety of the water supply".

The audit found Irish Water failed to test for cryptosporidium and giardia after a pump at Leixlip was out of action over the night of March 13-14.

It also failed to notify the HSE that protections against the bugs were compromised by the pump outage, reporting instead only an elevated level of ammonia.

When the EPA became aware of the full significance of the incident on March 15, it discovered Irish Water had failed to take samples to test for the bugs "in the critical period" after the pump failure.

The EPA asked for samples to be taken straight away but it was Friday, the lab was closed for the St Patrick's bank holiday weekend, and the samples were good for only 48 hours.

The earliest that samples could be taken was Sunday as they would survive for testing until the following Tuesday.

The samples were clear of cryptosporidium but giardia was present.

Extra testing for both bugs then continued for eight weeks.

The EPA report on the incident concluded: "Irish Water must ensure that the lessons learned from this incident are acted upon to prevent a recurrence, and to ensure the ongoing safety and security of the water supplied by Leixlip water treatment plant."

Irish Water said it could not comment as there were still live issues around the audit. It emerged as the EPA spent several hours inspecting the Leixlip plant to determine how this fresh cryptosporidium and giardia scare happened and if the issue was resolved.

Irish Water said tests on a water sample taken earlier this week were "satisfactory" but the results of tests on a second sample would be known today.

Public patience was wearing thin as the prospect of a bank holiday weekend without clean water loomed and shops continued to experience heavy demand for bottled water.

A number of swimming pools in the affected areas of Dublin, Kildare and Meath closed because of the contamination fears.

Irish Water said it did not tell pools to close but to consult the HSE if they had concerns. The HSE said it did not issue specific advice to pools to close but it has advised that cryptosporidium can survive the normal chlorine levels in drinking water.

While swimming pools have a higher level of chlorine, some pool operators decided to close as a precaution.

Meanwhile, Irish Water has pleaded guilty in a prosecution by the EPA over drinking water problems in County Cork.

The company faces charges arising from its alleged failure to provide test results showing that trihalomethanes (THMs) were within safe levels in the drinking water supply at Drimoleague and Kealkill.

Irish Water was to have submitted final reports with the all-clear before the end of 2018 but it accepted at Dublin District Court that it had failed to do so.

The case will come before the court again in January.