Water is the key to all living things. Unfortunately, dehydration is a common health risk faced by chameleons. Lack of water is not easily identified visually, but can have disastrous results. It is critical that you provide sufficient water in the "right" ways.
In nature, their water source is the dew drops that form and the rain that falls on leaves. To simulate this in captivity, we commonly use both a dripper and a spray mister.