SINGAPORE - Water is set to cost more here, as Singapore seeks to ensure long-term water security in the face of uncertain weather conditions.

An increase in water prices will be announced at the upcoming Budget, said Minister for the Environment and Water Resources Masagos Zulkifli. The country has also been making further moves to increase its desalination capacity.

The price increase will help ensure the reliability of the country's water infrastructure, as well as support reliable but more expensive sources of water like desalination.

Mr Masagos said at a tour of the partially completed Tuas Desalination Plant 3 on Tuesday (Feb 7) that the price of water has not been revised for many years and that it is underpriced.

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He explained that it is important to support the renewal of water infrastructure and ensure reliable delivery of water.

He highlighted the importance of alternative water sources like desalination in the face of uncertain weather conditions in the future, noting that Johor's Linggiu Reservoir may dry up completely if dry weather continues for the next two years.

Desalinated water is one of Singapore's Four National Taps, and is the most expensive because of the energy required to extract salt from seawater at high pressure. The other taps are Newater, water from local catchment areas and imported water.

Nevertheless, Mr Young Joo Chye, director of Engineering Development and Procurement at national water agency PUB, said: "Desalinated water is a key pillar of Singapore's water supply strategy. As a source of water that is independent of rainfall, it bolsters the reliability of our water supply against prolonged periods of dry spells and droughts."

Two desalination plants are now in operation here. They have a combined capacity of 100 million Imperial gallons a day (mgd), meeting up to 25 per cent of Singapore's water demand of 430mgd.

Desalination will meet up to 30 per cent of Singapore's water demand by 2060 when demand is expected to double.

The third desalination plant in Tuas, which will supply 30mgd of water, is 60 per cent complete and is expected to be finished by November this year at a cost of S$217 million.

It will be followed by a fourth and fifth plant in Marina East and Jurong Island by 2020.

In the latest development, PUB on Tuesday (Feb 7) asked four shortlisted applicants - Keppel Infrastructure Holdings, Sembcorp Utilities, Tuas Power and YTL Power International Berhad - to submit proposals for developing the fifth plant at Jurong Island.