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Vartry Water Supply Scheme


The new Vartry Water Treatment Plant is now operational, a major milestone in the upgrade of the Vartry Water Supply Scheme, which has supplied generations with water for over 150 years.

The new water treatment plant uses cutting edge treatment technologies to secure the supply of clean water for 200,000 people in North Wicklow and South Dublin.

The completion of the new water treatment plant means that current and future generations will benefit from a high quality, safe, secure and reliable water supply.

The major upgrade to the Vartry Water Supply Scheme will ensure that this scheme will continue its proud history of safeguarding the water supply for this highly populated and rapidly growing part of the country and continue to support its ongoing economic growth and development for generations to come.


Aerial view of Vartry Reservoir and water treatment plant in County Wicklow.

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.

Uisce Éireann invested €150 million in the Vartry Water Supply Scheme Upgrade project, to improve the scheme and ensure that water provided complies with water quality standards set out in the European Union Drinking Water Directive and the current, national Drinking Water Regulations.

This major upgrade included three key elements:

  • A new water treatment plant at Vartry - constructing a new water treatment plant on the site of the existing plant at Vartry – operational November 2021
  • A new link pipeline from Vartry to Callowhill - a 4km pipeline to secure the transfer of treated water from Vartry to Callowhill – operational December 2018
  • A new covered reservoir at Stillorgan – operational September 2021

What is happening now?

New Vartry Water Treatment Plant

The new Vartry Water Treatment Plant is now operational. The new water treatment plant uses cutting edge treatment technologies to secure the supply of clean water for 200,000 people in North Wicklow and South Dublin.

The delivery of this new Water Treatment Plant will facilitate the removal from the RAL of the seven water supply zones linked to Vartry, and will secure the water supply for much of the highly populated North Wicklow and South Dublin area for the coming decades.

Vartry water treatment plant

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.

Uisce Éireann has 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.

Now that the new water treatment plant at Vartry is operational, work will shortly commence on the decommissioning of the old water treatment plant and landscaping of the site.

Vartry to Callowhill Pipeline

In 2018, Uisce Éireann completed the new pipeline from Vartry to Callowhill. This pipeline replaced a four kilometre long rock lined tunnel that was at risk of collapse.

The four kilometre long tunnel, was part of the original Vartry Water Supply Scheme and had been chiselled by hand through hard, dense "greywacke" rock. Treated water flowed through the unlined rock over its 150-year service life, gradually eroding it towards risk of collapse. A pipeline connection was required to replace the tunnel and secure the water supply to over 200,000 people in Wicklow and Dublin. This work got underway in February 2017 and was completed in December 2018 and included 4km of pipelines from Vartry to Callowhill as well as a pumping station and related infrastructure

The new 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.

New Stillorgan Reservoir

The newly constructed covered reservoir at Stillorgan began operations in September 2021.  The new covered reservoir replaces the open reservoir, originally constructed as part of the Vartry Water Supply Scheme.

The Stillorgan Reservoir site has supplied drinking water to the community for over 150 years.

These reservoirs were open to the environment, which was not in accordance with current best practice, as it presented quality risks to the water supply.

The open reservoir meant that the treated drinking water was vulnerable to the risk of being contaminated by wildlife, animal waste, airborne material and could be polluted by people accessing the water.

The new covered reservoir eliminated these risks, ensuring a safer, more secure and sustainable water supply for over 200,000 customers in South Dublin.


Aerial view of Stillorgan reservoir

Contact us

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

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

Co. Dublin and Wicklow

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