Works progressing to address intermittent discoloration on the Cavanhill network

Information below is relevant until further updates are provided here or on our Supply and Service Updates section.

Uisce Éireann continues to prioritise works to address the intermittent water discolouration affecting some customers on the Cavanhill water supply, which supplies Dundalk and surrounding areas.

Discolouration issues in the Cavanhill supply are seasonal as rising temperatures over the summer are associated with increased instances of discoloration. Uisce Éireann is undertaking works both at the treatment plant and in the network to resolve and manage the issue. In a bid to reduce the impact of the intermittent discolouration, a targeted flushing programme has been underway since early June and will continue for approximately sixteen weeks.

In addition, a new pilot study which aims to find a permanent solution will commence in the coming weeks. This involves commissioning a new purpose-built containerised unit at the treatment plant to trial new filters which remove manganese from raw treated water. The study will identify the available treatment plant solutions to the discoloration. Results of the study are expected later on this year. 

Stephen Burke, Uisce Éireann’s Regional Operations Manager for the East, reiterated the focus on public health, stating “The increase in water temperatures during the summer months has led to intermittent instances of discolouration on the Cavan Hill water network. Our team is taking a two-pronged approach which involves the flushing of the network, and a pilot project to find an enduring solution.
Protecting public health is the top priority for Uisce Éireann. The water is safe to drink once it is running clear. We advise people not to drink discoloured water. In the event of discolouration, running the tap for several minutes - we recommend up to 20 minutes - will usually restore water to a clear colour. If the issue persists, we encourage customers to contact us directly. The customer care helpline is open 24/7 on 1800 278 278.”

Upgrade works to the treatment plant in 2021 were successful in removing organic material and have led to improvements in the colour of the water.  Since then, in a bid to eliminate the intermittent colour which can occur in the summer months, two further trials on the treatment process have taken place. These results have led to this pilot study which aims to find a permanent solution.

To protect public health, Uisce Éireann has also increased its sampling efforts with proactive investigative monitoring at customers' taps. Regular sampling is already carried out at customers' taps and on the network, along with operational sampling at the water treatment plant. This provides reassurance that the water is compliant once running clear and assists with investigations into discolouration reports. This information is helping to better inform us of how the network is performing on a day-to-day basis.

As part of Uisce Éireann's continuing commitment to keep the community informed, we are engaging with all local elected representatives and will continue to issue regular updates as work progresses.