National water agency PUB has called a tender for consultancy services to study the potential of underground water sources in the western and southern parts of the island, it said in a release on Friday.

The targeted areas with a potential source of water are known as the Jurong Formation and the three-year study will be awarded in July this year. It will comprise studying the development of a groundwater flow model in the formation, field investigations and a validation study.

Singapore's water demand currently stands at approximately 400 million gallons a day and is projected to almost double by 2060.

PUB has also embarked on a study to verify the feasibility of extracting groundwater from reclaimed land in Jurong Island. The project has been awarded and commenced in April 2013.