Arklow Plant Completion Lifts Wicklow’s Wastewater Compliance

Uisce Éireann says 93% of the utility’s treatment plants nationwide now meet EU standards, according to the latest EPA report

The completion of the €139 million Arklow Wastewater Treatment Plant has been highlighted as a major step forward for Co Wicklow’s water quality, as new figures show 93% of Uisce Éireann’s wastewater treatment plants nationally are now compliant with EU standards.

The figure comes from the latest Environmental Protection Agency report. Uisce Éireann says the Arklow plant, finished during 2025, has significantly improved the environmental quality of the Avoca River and the surrounding coastal waters. It also provides the capacity needed to support Arklow’s future growth.

Further inland, construction of a new wastewater treatment plant in Avoca is nearing completion and is expected to begin operating next year.

Once it is running, the utility says it will end the discharge of untreated wastewater to the Avoca River, improving water quality, supporting a healthier river ecosystem and boosting biodiversity.

Arklow Wastewater Treatment Plant 

Nationally, Uisce Éireann invested €454.4 million in wastewater infrastructure during 2025, up by more than €120 million on the €333 million spent in 2020. Total investment since then has passed €2.5 billion.

Raw sewage discharges were ended at Rathmullan, Ramelton, Ballycotton and Arklow last year, while Whitegate-Aghada came off the untreated agglomerations list in early 2026.

New infrastructure has now been delivered, or is under construction, in 41 towns and villages where raw sewage was previously discharged. Uisce Éireann says raw sewage discharges are down by more than 85% since 2014.

The utility accepts there is more to do, and acknowledges the EPA’s concerns about operational incidents. It says many of the problems stem from ageing infrastructure, parts of which have been in place for decades and were not designed for current demands.

The network is large, with more than 1,000 wastewater treatment plants, 2,300 pumping stations and over 26,000 kilometres of pipes. New organisational structures have been introduced to strengthen oversight and improve incident response.

Niall Horgan, Uisce Éireann’s Wastewater Compliance Senior Manager, said: “The progress we are seeing in Co Wicklow shows what sustained investment can deliver for communities and the environment. We have made significant progress in recent years, but we know there is more to do.”

He also appealed to households and businesses to think about what goes down the drain. “Fats, oils, grease and other unsuitable materials can cause blockages and place additional pressure on the wastewater network,” he said. Inappropriate materials in the system were behind a number of incidents last year.

Elsewhere, the €550 million Ringsend Wastewater Treatment Plant upgrade in Dublin was completed in 2025. Its compliance with the Urban Wastewater Treatment Directive was confirmed in September 2026 after a full 12 months of monitoring data.