Phocus2 is an acoustic data logger system designed for widespread use in detecting and localising leakage on water distribution systems. Large areas may be rapidly assessed. As a 'smart' logger, it can automatically determine the presence of a leak. This enables use in either survey mode or permanent installation. This logger gives a visual indication of leakage or can be used with software to produce graphical/tabular results. Acoustic logging is a cost effective method of reducing leakage to very low levels. Phocus2 allows water companies to 'focus' resources in the fight against leakage.