Electronics and water/moisture do not mix. If your iPad has become wet, it is very likely to have suffered internal damage.
Power Adapters and charging cables must always be kept dry. For the Power Adapter, when connected to AC-mains, any moisture will create an electrocution hazard to both you - and your electronics. Wet/damp charging cables may corrode and/or create a short circuit.
If your iPad or its Power Adapter have been exposed to water, you would be well advised to have them inspected by a qualified technician before attempting to use them again. You should visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to assess your iPad, Power Adapter and cable(s):
Genius Bar Reservation and Apple Support Options - Apple