Water-tight Singapore plugs the leaks to cut wastage

PETALING JAYA - Singapore has a non-revenue water level of 5 per cent, making it one of the most "water-tight" states in the world.

According to a document titled "Ensuring Low Unaccounted-For-Water" provided by the Public Utilities Board (PUB), the republic has 5,300km of water pipeline - about 600km more than Malacca - serving over five million people.

It said Singapore was able to reduce water wastage by finding and plugging its leaks as well as putting in good quality pipes.

To reduce the number of leaks arising from the corrosion of unlined galvanised iron pipelines, a survey was conducted in 1983 to identify and replace all unlined galvanised iron pipes and unlined cast iron pipes in the water distribution system with cement mortar-lined ductile iron pipes and stainless steel or copper pipes. The programme cost $56 million at that time, and took three phases to complete.

Other later steps included the replacing of 280km of old cast iron water mains by 2004 for S$87 million and replacing 120km of asbestos cement mains in 2008 for S$20 million.

Since the 1990s, PUB has enforced a guideline of three leaks per km of pipes per year, and has targeted to reduce this to two leaks per km of pipes per year.

It also has a computerised system with constant information on its mains, and its officers employ special leak detection methods.

In one case, the PUB studied hissing sounds coming from metallic pipes to detect and trace leaks.

Domestic water meters that register more than 4,000m3 or are older than 15 years are changed, while non-domestic ones are replaced after every two to seven years.