A credit-card sized electronic unit measuring water flow-rate by means of contactless ultrasonic transducers in distribution pipelines is presented. It acquires sensors data and transmits via LoRA WAN every hour dissipating only 340 µWh thanks to a low-power design. Power supply can be provided by the internal battery or a compact solar panel. Furthermore, this unit powers and communicate with a remote unit detecting water leaks by means of impedance measurements through the same four copper electrodes used for sensing on the pipe.