This sensor monitors leakage and sends an alarm when flooding or leakage is detected. The sensing device can be away up to 3 m from the main device. The unit can be mounted on every flat surface. The installation can be done with screws or double-sided tape. The ST812 is a battery-powered device, which is in non-operating state unless an action is detected. After a programmable sleeping time the device wakes up and sends status information. After this the unit goes back to non-operating state. Batteries can be changed without unscrewing the device from the door or frame. The unit will give a visual warning on the device and sends a warning to the Z-Wave controller, when batteries need to be replaced. The units send information to a controller or any other associated Z-Wave device. Up to 4 devices can be controlled from this device. The device needs to be included into a Z-Wave network by a remote control or any other Z- Wave controller. For configuration of certain behavior a static controller such as a PC with home automation software or a gateway is recommended.