EPA statement following audit at Leixlip water treatment plant, 8th November.

Date released: Nov 08 2019

EPA Statement following audit at Leixlip Water Treatment Plant, 8th November.


Irish Water, in consultation with the HSE, issued a precautionary boil water notice to over 600,000 people supplied by Leixlip Water Treatment Plant on the 4th November.  Since then Irish Water and Fingal County Council have been working to resolve the operational issues that gave rise to the Boil Water Notice.  Today (8th November) EPA inspectors audited the Leixlip Water Treatment Plant to confirm that the actions taken by Irish Water and Fingal County Council have rectified the operational performance issues at the plant.  The HSE, Irish Water and Fingal County Council were in attendance at the audit.

The EPA inspectors found that:

  • High turbidity levels in the raw water for a sustained period led to operational difficulties in the ‘old’ plant at Leixlip.  This resulted in unacceptably high levels of turbidity in the treated water, which meant there was a risk of breakthrough of microscopic parasites, Cryptosporidium and Giardia, into the water supply. 
  • The treatment plant appears to have been operating satisfactorily since Wednesday evening, 6th November.  Testing is ongoing to verify that the treatment barriers at the plant are fully effective.
  • Irish Water are undertaking filter upgrade works to address the immediate treatment deficit at the plant.  However, an additional treatment barrier may be required, such as ultraviolet disinfection as recommended in the EPA’s previous audit.  The EPA awaits Irish Water’s report on this matter which is due by 30th November.
  • As an immediate mitigation measure, Irish Water has reduced the throughput at the ‘old’ plant to provide a higher level of control over the quality of the treated water and to allow for faster upgrading of the filters at the Leixlip plant.  To facilitate this, production levels have been increased at Ballymore Eustace Water Treatment Plant.
  • Until the filter upgrade works are complete, the EPA has instructed Irish Water to undertake daily monitoring of Cryptosporidium and Giardia in the treated water at Leixlip Water Treatment Plant.
  • The ability of the Leixlip plant to maintain an appropriate level of performance remains a concern. Irish Water must notify the EPA and the HSE if the plant does not meet the level of performance required to ensure adequate treatment to ensure safe water.

The boil water notice will remain in place until the HSE is satisfied that the risk to public health has been addressed.  The EPA is working with the HSE, Irish Water and Fingal County Council to enable the boil water notice to be lifted as soon as it is safe to do so.

The paramount objective of the EPA is to ensure public health is protected.  Consumers in the affected areas should heed the advice of the HSE and boil their water for drinking water purposes, brushing their teeth, preparing food and infants bottles.