As says above they will get there water either in the veg/fruit being sprayed or bathed.
I have recently taken the water outta my viv as i am trying to copy more of a natural enviroment.
There is a great sticky about it all above its verry usefull i learnt quite a bit from it.
But on the other hand its pretty much each to there own some like bowels of water in some dont lol.
Humidity with a beardie can cause a respiary infection so i tend to leave all water out.
Not 100% fact just what i read