If placed on the floor, it detects leaks when the built-in sensor probe comes in contact with water. Once a leak is detected, the device will beep, the LED light will blink red and a notification will be sent, depending on your user settings, via email and in-app.
The detector can only take in a moderate amount of water, and if fully submerged, may become unusable. If this occurs, test the device for functionality after removing from water & drying. If it is still not performing properly, replace the device. If you expect a large flooding in the area where you install your Lyric water leak detector (e.g. near your water heater) that could submerge the unit, consider hanging it on the wall (with provided screws), and using the included 4 foot cable sensor for water detection. To cover an even larger area, purchase additional cable sensors to extend your coverage.