In this paper IoT application is illustrated through a real implementation of global household water consumption monitoring system across two countries in the Europe. A novel wireless water consumption monitoring system is designed, in which flow rate/temperature sensors are placed at different detection spots in a house to collect data, and the collected data is routed to a remote computer server via the home WiFi and the Internet. The designed system was installed and tested in 30 recruited households, 10 in Sosnowiec, Poland and 20 in Skiathos, Greece. It has been demonstrated that the global system is capable of providing remote, near real-time monitoring of water consumption in different households. Lessons learned from this real applicationy has been summarised to guide further work.