Irish Water has been granted the final go-ahead for the construction of an €80 million covered reservoir at Stillorgan.

The water company has welcomed the decision from planning authority An Bord Pleanála for the new covered reservoir at Stillorgan – the plan will secure the drinking water supply for 200,000 people.

The development includes 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 remainder of the site will be retained for future water services infrastructure to secure the long-term supply of drinking water for the community.

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 - both the EPA and HSE support the need to implement the longer term solution for the benefit of the community.  The site will remain an active treated water storage area and consequently public access will not be permitted. It is anticipated that construction will commence in 2018 and take approximately two years to complete.

Unacceptable contamination risk to public health

The existing Stillorgan site 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 to public health as the water supply is vulnerable to contaminated from wildlife, animal waste, airborne material and pollutants entering the supply from people accessing the water.

Irish Water lodged a planning application to Dun Laoghaire Rathdown County Council following a six week non-statutory public consultation undertaken by Irish Water in relation to the proposed new covered reservoir.

Planning permission was granted by Dún Laoghaire-Rathdown County Council on 1 June 2017 for the construction of a new covered reservoir, subject to the temporary provision of publicly accessible open space on an area of landscaped lands at the Stillorgan Reservoir site.

Irish Water appealed the planning condition as the locations of the decommissioned reservoirs need to be maintained for future water services infrastructure to secure drinking water for the community.

 An Bord Pleanála has now approved the planning application to ensure that the utility will retain the entire site for this future development.

John Prendeville, Project Manager with Irish Water, said:

“Irish Water is pleased that An Bord Pleanála has granted planning permission for the new covered reservoir at the existing Stillorgan Reservoir site.  The locations of the decommissioned reservoirs will be maintained for future water services infrastructure to secure drinking water for the community and Irish Water needs to retain the entire site for this future development.”