The zone in which leakage is located can be isolated by means of step testing using the MAST system. Each individual "step" quantifies the leakage level present by recording the reduction flow rate into the area.
Noise loggers are a cost-effective means of surveying to identify areas of potential leakage for further investigation. They operate automatically and have the advantage of not intervening in the distribution network. They are easy to deploy and are the preferred method of localising.