Minister Browne updates Cabinet on progress of Greater Dublin Drainage (GDD) project
- Published on: 4 February 2026
- Last updated on: 4 February 2026
Uisce Éireann has approved the Detailed Business Case for the project
Minister for Housing, Local Government and Heritage James Browne TD, today updated Government on continued progress by Uisce Éireann in bringing forward the Greater Dublin Drainage (GDD) project. Uisce Éireann’s Board has now approved the Detailed Business Case for the project.
The project, with an estimated cost ranging from €1.9 billion to €2.3 billion, will be one of the largest wastewater infrastructure projects in Ireland’s history. The new treatment plant for the Greater Dublin Area will provide the additional treatment and network capacity to support the long-term sustainable growth of the Greater Dublin Region, providing infrastructure for new housing, and ensuring that Ireland continues to meet our objectives under European law.
Minister Browne emphasised:
“The Greater Dublin Drainage project is critical to facilitate growth in the Greater Dublin Area and to help us in achieving the aims of Delivering Homes, Building Communities, our new housing action plan.
This project is progressing well, with Judicial Review proceedings resolved late last year and the project having now secured planning permission. Uisce Éireann’s Board have now approved the Detailed Business Case for the project, a crucial milestone, and Uisce Éireann is taking all possible measures to accelerate the delivery of this project. Given the strategic importance of this infrastructure, my department will do everything necessary to support its delivery and bring it to the next stage of project delivery.”
Uisce Éireann will proceed to issue pre-qualification tender documents for the project this week.
The Greater Dublin Drainage project, along with Uisce Éireann’s other major infrastructure project, the Water Supply Project for the Eastern and Midlands regions, reflect significant Government investment in water infrastructure to support development. These two projects together will help to secure future economic growth, development and especially housing delivery, not just in Dublin, but across the east and midlands.
ENDS
Note for Editors
The Greater Dublin Drainage Project (GDD) is the strategic response to increasing wastewater treatment capacity and network resilience in the Greater Dublin Area (GDA). It involves the construction of a new 500,000 Population Equivalent (PE) Wastewater Treatment Plant (WwTP) in Clonshaugh, a 14km orbital sewer between Blanchardstown and the WwTP, and an 11km outfall pipeline to the discharge point 6 km off the coast of north county Dublin.
The GDD project is situated in the southern fringes of Fingal, immediately outside the M50 motorway in Co. Dublin. The Project will serve the north-west quadrant of the existing Ringsend catchment. The diversion of the load to the GDD WwTP will reduce the load to the Ringsend WwTP and release critical network to cater for planned growth elsewhere in the Ringsend catchment. This diversion of load will also enable future growth in the GDD catchment (Leixlip, Blanchardstown, Clonee, Dunboyne, Ashbourne & Ratoath). These catchments are strategic growth areas, both in terms of housing and industry.
The GDD is an “inflight” project, and did not go through Approval Gate 1 (AG1) - Preliminary Business Case stage of the Infrastructure Guidelines. Uisce Éireann’s Board have approved the Detailed Business Case (AG2), and the Final Business Case for the project will come before Government, in due course (mid–2028), to proceed at Approval Gate 3 under the Infrastructure Guidelines.