Automatic meter reading (AMR) provides real-time consumption data, enabling to collect a huge amount of information about daily, even hourly, consumptions. It is then easy to assess lost volumes on the network, using supplied volumes information. However, because of the multiple components of water losses, the metering and calculation inaccuracies, the occurrence of new (detectable) leaks is hard to detect. Therefore this paper aims at proposing a user-friendly statistical tool that helps to quickly and reliably detect new leakage occurrence. The use of process control chart (like exponential weighted moving average) enables us to detect changes in the water loss time series, in particular, a new leak occurrence.