Hi...as per my knowledge Water meters are installed at each of the inlets in an apartment, and the totalizers are placed as near as possible. Data from these smart meters is sent to the controller/totalizer, which is then sent to the cloud for further actions. Access to the cloud data via apps enables users to switch on/off the valve. For uninterrupted performance, the meters have a backup power source that can also be solar based. However, the cost of solar based batteries is still quite high and suppliers should keep track of OpEx of the projects to make them viable in the long run.