While the device is water resistant, it isn't completely waterproof. If the device is submerged in water or if water gets into the top of the device, it can become permanently damaged.
The leak detector is open to the surrounding air through the holes in the top of the device in order for it to be able to measure temperature and humidity.
The device interior under the holes on the top of the detector has a series of baffles and compartments to direct water away from the temperature and humidity sensor which is inside this area. The rest of the printed circuit board is sealed off from this area by a rubber gasket. The baffles direct any water that gets into the top of the device to a drain hole that drains out of the bottom. This provides some protection for the electronic circuitry from water dripping on to the unit.
However, if a directed jet of water were to shoot directly into the open holes or if the device is submerged this could lead to water getting into the temperature and humidity sensor, and will be likely to permanently damage it.
For more information on our product warranty, please see: What is the warranty for Roost smart devices?