The new covered Stillorgan Reservoir replaced the open reservoir originally constructed as part of the Vartry Water Supply Scheme, which has served the community for more than 150 years.

The project was necessary to ensure a secure and sustainable supply of water to over 200,000 people in South Dublin.

The Stillorgan site was one of the last remaining open service reservoirs of treated drinking water of its kind in Europe. Treated drinking water exposed to the environment presented an unacceptable contamination risk to public health, as the water supply was vulnerable to contamination from humans, wildlife and environmental sources.

This €80 million development included the draining of one of the reservoirs and the construction of a new covered reservoir. Once the new covered reservoir was operational, the other two open reservoirs were decommissioned, and landscaping of the site took place. The new covered reservoir has the capacity to support future growth until 2031.

The remainder of the site has been retained for future water services infrastructure to secure the long-term supply of drinking water for the community.