Irish Water will be submitting a planning application to Dún Laoghaire-Rathdown County Council in the coming weeks, seeking permission for the construction of a new covered reservoir, to be built at the Stillorgan Reservoir site. The Stillorgan Reservoir site has supplied drinking water to the community for 150 years. This new covered reservoir is essential to safeguard the quality of the drinking water for 200,000 customers. The existing Stillorgan site contains three open water reservoirs which store treated drinking water prior to its distribution to customers. This is one of the last remaining open service reservoirs of treated drinking water of its kind in Europe. Treated drinking water exposed to the environment presents an unacceptable contamination risk.

The Stillorgan Reservoir Upgrade Project will include the draining of one of the reservoirs and the construction of a new covered reservoir. Once the new covered reservoir is operational, the other two open reservoirs will be decommissioned, and landscaping of the site will take place.  The new covered reservoir will have the capacity to support future growth to 2031. The locations of the decommissioned reservoirs will be maintained for future water services infrastructure to secure drinking water for the community. Irish Water held two public information evenings in August and September this year, to coincide with a six week non-statutory public consultation on the proposed new covered reservoir, to be built at the existing Stillorgan Reservoir site. Members of the public and interested stakeholders came along to the events to meet the project team who were on hand to answer any questions on the project. Interested parties were also invited to submit their views on the upgrade to the Stillorgan Reservoir by the 14 September. A consultation report and the Environmental Impact Statement (EIS) will be submitted in support of the planning application to Dun Laoghaire-Rathdown County Council.

Geoff O’Sullivan, Project Manager with Irish Water, said “Covering the reservoir will safeguard the quality of drinking water for the community and provide a long-term solution for the safe and sustainable management of the water supply for the next 15 years. This is a priority project for Irish Water and we are committed to investing approximately €80 million to ensure the upgrade to the reservoir provides the long term solution that is required to secure the water supply. The Stillorgan Reservoir has served the community for over 150 years and this project will ensure it continues to do so. The two decommissioned reservoir areas will be maintained by Irish Water for future water infrastructure development to ensure that the community continues to have a safe, sustainable water supply for the future”. 

Irish Water has already invested €3.4 million to improve the disinfection of drinking water stored in the Stillorgan Reservoir enabling the removal of the Stillorgan Reservoir from the EPA’s Remedial Action List. The investment in a new covered reservoir is a significant additional measure to protect and upgrade the water quality in the reservoir, and the EPA and HSE support the need to implement this longer term solution for the benefit of the community. 

An Environmental Impact Statement (EIS) has been prepared in accordance with national and EU legislation and will be submitted in support of the planning application.  The EIS will assess all the potential impacts on the environment which could result from the development and proposed mitigation measures to minimise the residual impact. Once the planning application is submitted, Dun Laoghaire-Rathdown County Council will undertake a period of statutory consultation. 

Subject to planning permission being granted, it is anticipated that construction will commence in 2018 and take -approximately two years to complete. 

Further information is available on our Stillorgan project page. 



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