Water Supply and Sanitation in Singapore - Water Sources and Integrated Management

Water Sources and Integrated Management

The water resources of Singapore are especially precious given the small amount of densely settled land. Singapore receives an average of 2,400mm of rainfall annually, well above the global average of 1,050mm. The constraint is the limited land area to catch and store the rainfall, and the absence of natural aquifers and lakes. Therefore Singapore relies on four water sources, called "the four taps":

• rainfall, collected in artificial reservoirs that collect water from carefully managed catchment areas (200-300 million gallons per day, depending on rainfall),
• Imported water from Malaysia (up to 250 million imperial gallons (1,100,000 m3) per day, according to the 99-year agreement signed in 1962, plus an additional quantity under the 1990 agreement),
• Reclaimed water (producing what is called NEWater) (up to 115 million imperial gallons (520,000 m3) per day, officially only "30% of demand"), and
• Seawater desalination (up to 50 million imperial gallons (230,000 m3) per day, officially only "10% of demand").

This "four tap" strategy aims to reduce reliance on supply from Malaysia by increasing the volume supplied from the three other sources, or "national taps". Since water demand in 2011 was 380 million imperial gallons (1,700,000 m3) per day, Singapore could actually already have been water self-sufficient in 2011 except in years of very low rainfall. The official figures downplay the share of reclaimed and desalinated water in water supply, and thus the ability of the country to be self-sufficient. However, the Chairman of PUB admitted in 2012 that water self-sufficiency could be achieved well before the target year of 2061.

In Singapore, water management is closely integrated with land management. The latter is tightly controlled in order to prevent any pollution of water resources through sewage, sullage or other sources of pollution. The management of water supply, sanitation and stormwater drainage is managed by a single agency, the Public Utilities Board, in an integrated and coordinated manner.