Wednesday, 08 October 2025
Uisce Éireann Begins €18 Million Upgrade of Claremorris Wastewater Treatment Plant Uisce Éireann has commenced a major €18 million upgrade of the Claremorris Wastewater Treatment Plant in County Mayo. This essential project will increase the plant’s capacity by 65%, improve water treatment performance, and help meet environmental obligations under the EU Water Framework Directive. Project […]
Uisce Éireann has commenced a major €18 million upgrade of the Claremorris Wastewater Treatment Plant in County Mayo. This essential project will increase the plant’s capacity by 65%, improve water treatment performance, and help meet environmental obligations under the EU Water Framework Directive.
The upgrade will see the treatment plant’s design capacity increase from a population equivalent (PE) of 5,333 to 8,800, enabling it to better serve the growing population and future development needs of Claremorris. The modernisation is designed to enhance the quality of treated wastewater, contributing to the protection of local waterways and surrounding ecosystems.
Patrick Greene, Programme Manager at Uisce Éireann, stated:
“This upgrade represents a major investment in Claremorris and underlines our commitment to safeguarding the environment while enabling sustainable development. By boosting the capacity and modernising key treatment processes within the existing site boundary, we will ensure that the plant can cater for current and future needs, contribute to biodiversity conservation, and support the social and economic ambitions of the community.”
The Claremorris and Lough Mask upgrades both reflect Ireland’s ongoing efforts to comply with the EU Water Framework Directive, which sets legally binding targets for improving water quality across Europe.
Upgraded plants must meet stricter standards for nutrient removal (especially nitrogen and phosphorus), which, if left untreated, can harm freshwater ecosystems. Modernising infrastructure ensures that treated water released into rivers, lakes, or groundwater systems doesn’t degrade the ecological status of these environments, particularly important for Mayo’s interconnected system of lakes and rivers, such as Lough Mask, Lough Corrib, and the River Robe.
The works are being carried out by Veolia Water Ireland on behalf of Uisce Éireann. All construction activity will take place within the existing plant boundary to minimise disruption to the community.
The project commenced in 2025 and is expected to be completed by autumn 2027.
Veolia Water Ireland, the delivery partner for both the Claremorris and Lough Mask upgrades, reflects a growing trend in public-private partnerships (PPPs) for essential infrastructure.
By combining public funding and policy oversight with private sector expertise and project execution, these partnerships help ensure projects are delivered efficiently, on time, and to the high technical standards required for modern water treatment. Their involvement across multiple major projects in Mayo also enables a regional consistency in quality and process.
The upgraded facility will support Uisce Éireann’s efforts to:
Improve wastewater treatment standards to protect receiving waters such as rivers and lakes
Ensure compliance with the EU Water Framework Directive
Enable population and economic growth in Claremorris and surrounding areas
Support biodiversity by reducing nutrient loads and improving water quality
This investment is part of Uisce Éireann’s wider strategy to upgrade wastewater infrastructure across County Mayo, involving works in several towns and villages to ensure all communities have access to high-quality, reliable wastewater services.
While the Claremorris plant is set to be completed by 2027, and the Lough Mask upgrade by 2028, their impact will extend decades beyond that. Both projects are designed to serve current populations and accommodate significant future growth, with engineering designs that anticipate increased demand, climate variability, and stricter future environmental regulations.
This kind of long-horizon infrastructure planning reflects the Irish government’s growing emphasis on climate adaptation and regional resilience, ensuring that today’s investments avoid tomorrow’s bottlenecks.
According to Uisce Éireann, the €29 million programme of upgrades across Mayo includes work in:
Belmullet
Killala
Charlestown
Kiltimagh
Louisburgh
Swinford
Each project is aimed at either eliminating raw or poorly treated discharges, increasing treatment capacity, or ensuring compliance with national and EU environmental standards.
Although the specific technologies in Claremorris and Lough Mask haven’t been detailed publicly, modern upgrades typically involve:
Improved sludge management systems
Automation and real-time monitoring
Enhanced filtration or disinfection methods
These may seem like technical upgrades, but they have far-reaching implications—from reducing energy use and emissions to ensuring water quality during extreme weather events, a growing concern under Ireland’s changing climate.
The €18 million upgrade to the Claremorris Wastewater Treatment Plant is a key milestone in Uisce Éireann’s broader investment in Mayo’s water infrastructure. By expanding capacity and improving treatment quality, the project supports environmental protection, community health, and long-term sustainable growth in the region.
To stay updated on progress, visit the official Uisce Éireann Mayo Projects page.
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