Yes, it is generally safe to put water in an air fryer to clean it because the steam helps lift any baked-on grease and food.
However, you need to make sure you don’t overfill the basket with too much water, and you need to be careful removing the hot water afterwards.
To clean your air fryer using water, add 2-3 tablespoons into the basket alongside 2-3 drops of dish soap. The water should only just cover the base of your air fryer basket. Set the air fryer to low-medium temperature and let it run for 3-5 minutes.
The steam created by the water and soap will loosen any stuck-on food and grease, making it easier to wipe clean.