Project Background

The Vartry Water Supply Scheme provides drinking water for a supply area stretching from Roundwood, through north Wicklow up to south Dublin and serves over 200,000 people. It was developed by Dublin Corporation in the 1860s and includes two reservoirs, a water treatment plant, a 4km tunnel under Callowhill and 40km of trunk mains that deliver water to storage reservoirs at Stillorgan in Dublin. The scheme was a significant engineering feat, with much of the ground and building works being carried out and completed by men using only picks, shovels, horses and carts. A British Pathé archive film shows the opening of the second upper reservoir in from 1923. 

At the time, the scheme greatly improved sanitation in Dublin City and helped reduce outbreaks of cholera, typhus and other diseases associated with contaminated water. The original Vartry Water Supply Scheme still provides drinking water to around 15% of the Greater Dublin Area.

Vartry to Callowhill Pipeline

Irish Water has completed the new pipeline from Vartry to Callowhill. This pipeline secures and safeguards the water supply for more than 200,000 people in north Wicklow and south Dublin, one of the most densely populated areas in the country. The completion was marked by Cathaoirleach of Wicklow County Council, Cllr Pat Vance, Minister for Housing, Planning and Local Government, Eoghan Murphy TD, Tony Keohane, Chairman of Ervia, and Eamon Gallen, MD of Irish Water, at an event at the Vartry Water Treatment Plant.

Co. Dublin and Wicklow
In Progress

Vartry to Callowhill Pipeline

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Vartry Water Treatment Plant

Planning permission for the upgrade works to the Water Treatment Plant was granted, subject to six planning conditions, by Wicklow County Council in November 2016. The details are available on the Wicklow County Council website. The consent was subsequently appealed by third parties. In January 2018, An Bord Pleanála granted consent for the planned upgrade subject to 8 planning conditions.

Stillorgan Reservoir Upgrade Project

Planning permission for the Stillorgan Reservoir Upgrade Project was granted, subject to sixteen planning conditions, by Dún Laoghaire-Rathdown County Council on 1 June 2017.  Irish Water lodged an appeal to An Bord Pleanála seeking the removal of one of the conditions which is to provide publicly accessible open space within the site. In December 2017, An Bord Pleanála approved the planning application to ensure Irish Water will retain the entire site for this future development.

Project Overview

Project Overview

Irish Water is making a significant investment in the Vartry Water Supply Scheme to ensure a safe and sustainable water supply for the north Wicklow and south Dublin areas. This investment will ensure that water provided complies with water quality standards set out in the European Union Drinking Water Directive (1.) and the current, national Drinking Water Regulations (2.).

  1. Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption
  2. European Union (Drinking Water) Regulations 2014

What is involved?

  • Construction of a new Water Treatment Plant on the site of the existing plant at Vartry.
  • Construction of a 4km pipeline to secure the transfer of treated water from Vartry to Callowhill pumping station which was completed on 4 February 2019. 
  • Decommissioning of existing Water Treatment Plant.
  • Decommissioning of Vartry tunnel to allow for remediation works to be carried out.
  • Replacing ageing pipes and fittings within the dam of the Vartry Reservoir.
  • Improvements to the Vartry dam spillway to allow for more intense rainfall events resulting in larger spills from the reservoir to ensure public safety.

It is important to note that the works are focused on securing the existing supply for customers, no additional water will be abstracted from the Vartry reservoirs or catchment area.

We have also committed to release sustainable freshwater flows to the River Vartry downstream from the new Water Treatment Plant.  This protection is especially important at times of drought. The freshwater flows will come directly from the existing Vartry reservoir and is in addition to the natural flows from groundwater, other tributaries in the catchment and from the reservoir itself when the water levels are high.

This will be the first time in the 150 year operation of the Vartry Water Treatment Plant that such a guarantee will be used to safeguard the ecology of the river.  Further details are available in the FAQs.

This project is closely linked to the Stillorgan Reservoir Upgrade Project which will provide covered water storage in Stillorgan and associated pipeline modifications that will improve the protection of the water supply to the network.

Contact Us

Please contact us with any questions or queries about this project.

  • Telephone: 1890 815 661
  • Email:
  • Post: Vartry Water Supply Project, Colvill House, 24-26 Talbot Street, Dublin 1

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