Every Drop Counts: Singapore’s Water Security Strategy (Part 1)

Asnith Muniraju, Charmaine Lee and Kevin Chew
8 hours ago
8 min read

In this Explainer, find out...

Why is water a critical concern for Singapore?
How does Singapore expand and diversify its water supply?
How reliable is Singapore’s “Four National Taps” strategy?

Introduction

The desert planet Arrakis is a place of arid conditions, vast sandstorms and colossal worm-like creatures. Facing extreme water scarcity, its native Fremen people build “windtraps” that capture air moisture and wear specialised suits that recycle bodily fluids. In their eyes, to shed tears is to waste a most precious resource. This is the world of Dune (1965), an interstellar science fiction novel written by Frank Herbert. Singapore may be no desert (and certainly not one inhabited by giant sandworms), but its national narrative echoes the Fremen’s in its emphasis that “every drop counts”.

In Singapore, water underpins public health, daily living and economic activity. For a developed nation that consumes 440 million gallons of it a day, water is indispensable. Since its independence in 1965, a perennial concern for Singapore has been to provide its people with sufficient, clean water. Over the years, the Government has developed an extensive water policy that involves both expanding the water supply and managing its demand.

In the first part of this Policy Explainer, we focus on the supply-side of this water policy, tracing its history and evaluating its reliability. Before doing so, however, it is necessary to consider why water remains such a critical concern for Singapore.

Why is Water a Critical Concern?

Domestic Scarcity, Diverse Needs

Singapore faces the dual issue of water scarcity and high water demand. As an island-nation with a total land area of about 744.3 km², Singapore has limited capacity to build reservoirs that collect and store rainwater. It also lacks natural freshwater resources such as large rivers, springs or glaciers. These inherent constraints handicap Singapore’s ability to secure a sufficient and sustainable water supply.

Exacerbating this, Singapore uses a lot of water. Households need water for day-to-day tasks like showering, cleaning and doing laundry. For a densely populated city-state like Singapore, this becomes a significant source of water demand. In 2024, local household water consumption stood at 142 litres per person per day. Beyond domestic consumption, water is also needed to sustain various industrial and business operations. Non-domestic water needs (i.e., water use excluding that of households) are expected to account for more than 60 per cent of total water demand by 2065, up from 55 per cent currently (see Figure 1).

Figure 1: Current and Future Water Consumption by Homes and Industries Respectively

In particular, technological sectors like artificial intelligence, semiconductor manufacturing and biomedical technology create an unprecedented demand for water. According to PUB, Singapore’s National Water Agency, one semiconductor fabrication plant can consume the equivalent of 500 swimming pools of water daily. The expansion of these water-intensive industries is swelling local water demand — it is projected to almost double by 2065. Faced with water scarcity and a simultaneously growing need for it, it is no wonder that Singapore regards water as a serious concern.

Historical Vulnerability

Another complicating factor is Singapore’s heavy dependence on Malaysia for sustaining its own water supply. This reliance on imported water dates back to Singapore’s merger with Malaysia and its subsequent separation. On 16 September 1963, Singapore merged with the Federation of Malaya, Sarawak and North Borneo to form the Federation of Malaysia. In the lead-up to this, Singapore signed two water supply agreements with the Malaysian state of Johor in 1961 and 1962 respectively. The pacts allowed Singapore to buy raw water from Johor at a fixed price.

However, following deep tensions between the two governments, Singapore separated from Malaysia to become an independent state on 9 August 1965. As such, the water agreements became international treaties between two sovereign states. Both parties guaranteed the agreements in the Independence of Singapore Agreement 1965, which was registered with the United Nations. Despite this, water remained an area of contention between Singapore and Malaysia, as the two sides had repeated disagreements over the price of imported water and the future supply of water after current pacts expire. Against this backdrop of political uncertainty, Singapore saw its dependence on Malaysian water as a significant vulnerability.

Climate Volatility

Environmental factors are expected to pose further risks to Singapore’s water supply. Climate change refers to the long-term shifts in global temperatures and weather patterns, primarily driven by human activities that generate greenhouse gases. It is likely to bring about increasingly irregular rainfall patterns and longer periods of drought in Singapore. This can strain the nation’s management of water resources and undermine the reliability of its water supply.

Considering these complicating factors, it is easy to see why, for Singapore, every drop really counts. Domestic water scarcity, high consumption levels and a lack of self-sufficiency compel the Government to treat Singapore’s water security as a critical concern.

The “Four National Taps”

To manage these risks, Singapore has sought to both expand and diversify its water supply. This meant obtaining its water from four different sources, coined as the “Four National Taps”:

Local catchment water;
Imported water;
NEWater; and
Desalinated water.

Let us explore each “tap” more closely.

(i) Local Catchment Water

The first source of Singapore’s water comes from local catchments. These refer to land areas where rain falls and collects into a common water body. In the 1960s, Singapore’s domestic water supply mainly came from three catchments: the Seletar, Peirce and MacRitchie reservoirs. These reservoirs were protected, meaning that no development is allowed on their land.

However, as the population and economy expanded, land demand for housing and industrial developments grew. Facing competing land uses, the Government decided to create unprotected catchments, where some development was allowed but restricted to residential estates and non-chemical industries. The first such catchments were developed in the late 1970s.

On top of this, Singapore cleaned up polluted waterways so that they could also be used to harvest rainwater. One such project was the ambitious clean-up of the highly polluted Singapore River and Kallang Basin between 1977 and 1987.

As a result of these past efforts, Singapore currently has a total of 17 reservoirs (see Figure 2). Altogether, water catchment areas make up two-thirds of the country’s land surface, with plans to increase this figure to 90 per cent by 2060. Local catchment water, Singapore’s first “National Tap”, can meet at least 10 per cent of the country’s water needs.

Figure 2: Map of Singapore’s Reservoirs and Water Catchment Areas

(ii) Imported Water

A second source of Singapore’s water is imported from neighbouring Malaysia. This importation arrangement has been secured through two long-term agreements between the two countries, dating back to the 1960s.

The first water agreement was signed in 1961. Under it, Singapore was entitled to draw an unrestricted amount of raw water from the Tebrau and Scudai Rivers in nearby Johor. On top of annual land rental fees, Singapore was to pay RM0.30 for every 1,000 gallons of water it drew. Singapore also had to provide Johor with treated water amounting to 12 per cent of the imported water volume, at a price of S$0.50 per 1,000 gallons. The 1961 Water Agreement lasted 50 years and expired in 2011.

The second water agreement was signed in 1962. It granted Singapore the right to draw up to 250 million gallons of water per day from the Johor River. In exchange, Singapore had to supply Johor with treated water amounting to two per cent of the imported water volume. The prices remained the same as in the 1961 Water Agreement. Valid for 99 years, the 1962 Water Agreement will expire in 2061.

To supplement the 1962 Water Agreement, PUB and the Johor government signed a third pact in 1990. It allowed Singapore to construct and operate a dam in Sungei Linggiu to facilitate the extraction of water from the Johor River. Singapore could then purchase this water at a price that is based on a fixed formula. The 1990 agreement will similarly expire in 2061.

Together, the agreements enable Singapore to import a steady supply of water. Imported water, the second “National Tap”, can supply up to 60 per cent of Singapore’s water needs.

(iii) NEWater

Singapore’s third water supply is “NEWater”, which is what PUB calls its highly treated reclaimed wastewater. After decades of technological experimentation in water reclamation, Singapore launched NEWater in 2003 with the opening of two treatment plants. The NEWater production process involves multiple stages (see Figure 3). First, wastewater is collected and treated at conventional water reclamation plants. The treated water is then further purified at NEWater facilities through a three-step filtration process (comprising microfiltration, reverse osmosis and disinfection). This produces high-purity NEWater that consistently surpasses World Health Organisation guidelines.

Presently, Singapore has five operational NEWater plants, whose combined capacity represents 40 per cent of national water demand. The Government expects this share to rise to 55 per cent by 2060.

(iv) Desalinated Water

The last source of Singapore’s water comes from the sea. Desalinated water is suitable for human consumption, and is produced by artificially removing salt from seawater. This process takes place at specialised facilities — the first of which opened in Tuas in 2005. Four more desalination plants have been built since, with tentative plans for a sixth.

Together, the five existing desalination plants can meet up to 43 per cent of current water demand. The Government’s plan is for NEWater and desalinated water, the third and fourth “National Taps”, to supply up to 85 per cent of water demand by 2060.

HOW RELIABLE ARE THE “FOUR NATIONAL TAPS”?

The diversified nature of Singapore’s water supply is key to ensuring its long-term resilience. Whereas some water resources may be more weather-dependent and less reliable, there exist other “taps” to fill this gap.

For instance, local catchment water depends on rainfall patterns, which are becoming more unpredictable with climate change. Scaling the capacity of reservoirs is also challenging given Singapore’s land scarcity. Meanwhile, imported water is similarly weather-dependent, in addition to coming with its own political risks. The bilateral water pacts are not just time-limited (expiring in 2061) but also susceptible to challenges from Malaysia. For example, its then-Prime Minister Mahathir Mohamad threatened to cut off water supply to Singapore in 1998.

To safeguard its water supply, Singapore is transitioning away from imported water, to more self-sufficient and weather-resilient sources like NEWater and desalinated water. Both “taps” employ innovative technologies to harness potable water from sustainable sources — NEWater from waste streams, and desalinated water from the sea. The Government’s plans to boost these capacities will go a long way in strengthening both water and national security.

That said, NEWater purification and especially desalination are costly, energy-intensive processes. Relying on these taps may only end up trading Singapore’s water vulnerability for increased energy dependency. This prospect is particularly worrying amidst rising global geopolitical tensions. Recent conflicts in the Middle East and between Russia and Ukraine have shown how volatile the energy market can be. This may turn into a substantial liability for an energy importer like Singapore. Indeed, Minister for Defence Chan Chun Sing has recognised this challenge. As he observes, “if water has been the existential challenge in the last 50 years, clean, renewable and sustainable energy will be our existential challenge for the next 50 years”.

Conclusion

In the first part of this Policy Explainer, we traced Singapore’s signature “Four National Taps” policy to an underlying concern about its water security. Comprehensive as this strategy may be, it may not be able to fully address the challenge alone.

Moving beyond supply-side measures, how does Singapore moderate local water demand? And how does its overall water policy compare to that of other water-scarce countries? Find out more in the second part of this Policy Explainer.

This Policy Explainer was written by members of MAJU. MAJU is a ground-up, fully youth-led organisation dedicated to empowering Singaporean youths in policy discourse and co-creation.

By promoting constructive dialogue and serving as a bridge between youths and the Government, we hope to drive the keMAJUan (progress!) of Singapore.