Question
Sand Boas need warm/hot temperatures and very low humidity, generally speaking. During shedding, for snakes having trouble, especially eye caps, I've read that putting a water source (or humidity source) in the boa's environment can help. I'm concerned about the ability to retain the standard humidity levels though.
Is it generally recommended to leave a water dish in the tank, full time? What about only during shedding?
Answer
Wouldn't worry about it and just try it.
Considering it's still water (no sprinkler or any other movement) it should be fine, especially short term, without causing any significant and global change.
I assume you've got some humidity meter? Is so, just try and see how/if conditions change.
Either way it will also depend heavily on your actual terrarium. With low air circulation, you might not want to leave the bowl 24/7. With open/good ventilation you might be able to leave it there as well.
Answered By - Mario