Processes to Determine Leakage in Underground Water Pipes

Mr Leon Perera asked the Minister for Sustainability and the Environment (a) what are the processes used to determine whether underground water pipes are leaking, in cases where water appearing above ground is unlikely due to other causes; (b) what is the error rate for such checks; and (c) whether more accurate processes can be deployed upon appeal in specific cases, where there is a suspected error in the detection of a leaking underground water pipe.

The Public Utilities Board (PUB) has a comprehensive leak detection programme to pick up leaks as early as possible. PUB deploys a network of sensors that monitor the water pressure, flow and acoustics to allow early detection of leaks in our water pipes. PUB also conducts leak detection checks on its pipeline network at least once a year, and more frequently for pipelines that are near construction activities or that had experienced leaks previously. The rate of water losses through pipe leakage in Singapore, at about 8% of total water demand, is among the lowest in the world.

PUB also responds promptly to feedback of water seeping from the ground. If there is a water pipe in the vicinity, PUB will utilise leak noise data loggers to survey and identify any leak along the water pipe, followed by leak locators to pinpoint the exact location of the leak. Excavation will then be carried out to expose and repair the water pipe.

If there is no water pipe in the immediate vicinity, PUB will collect water samples to ascertain its source. Should the water quality of the samples match that of PUB-supplied water, PUB will widen the survey area to locate the potential leak. Otherwise, the seepage is likely due to groundwater and PUB will work with the relevant agencies or landowners to channel the groundwater to the nearest drain.