Howit it safe to use a wireless charger, when you phone is saying water is detected and to unplug your device

If you actually do have water in your device, no it is not safe to charge it, wired or wirelessly. Make an appointment at the Genius Bar to have it diagnosed.

Genius Bar Reservation and Apple Support Options - Apple

Make an appointment at the Apple Store or take the phone to an authorized Apple Service shop to have it checked.

You can find an authorized Apple Service shop using the link just below:

Find Locations