Developing new water sources through the Four National Taps constitutes half the strategy to ensure a sustainable water supply in Singapore. The other half is managing water demand and encouraging water conservation. Arguably, this can even be regarded as the more important half, given the physical and cost limitations of building new water sources indefinitely.

A single user increasing his water consumption may have little impact on the country's water resources, but if the entire population behaves likewise, this will not be sustainable. Furthermore, the prudent use of water involves important social habits and behaviours that take time to be inculcated, and hence any desired behavioural outcomes cannot simply be achieved overnight. Therefore, the thrust of any effective water demand management strategy must be to reach out to each and every user, be it an individual or organization, and ensure that such efforts are sustained over time.

SINGAPORE'S WATER DEMAND

Water consumption for the domestic sector in the last few decades has increased as a result of rapid industrial, economic, and social developments in Singapore. Up until 1995, the growth in domestic water consumption outpaced population growth. In 1965 when the population was at 1.9 million, domestic demand for potable water was 142,000 cubic metres per day (75 litres per capita per day). By 1994, the population had gone up by about two times, but domestic water demand had increased by more than four times (175 litres per capita per day). Such high demand growth puts a huge strain on Singapore's limited water resources and is not sustainable.