Using distilled water with the Xiaomi Robot Vacuum X20 Max can actually cause problems.

- Many modern vacuum and mopping robots, including the Xiaomi Robot Vacuum X20 Max, have a water level measurement in the water tank based on conductivity. However, distilled water has very limited or no conductivity, which can cause the robot to report an empty water tank even though the tank is full.

- This can lead to malfunctions, such as the robot returning to the station or notifications on the smartphone, even though the tank is not empty.

- It is therefore recommended to use tap water, although this can cause limescale deposits. Alternatively, you can use special cleaning agents or descaling agents for vacuum and mopping robots to prevent or reduce limescale deposits.

I use distilled water myself and have had no problems with it so far.