Hot glue Safe

I want to glue a section of rock were water will flow, will i need to worry about the water becoming contaminated? This isnt his drinking water...well, he should be drinking from it.

Is this a waterproof glue? If so then it shouldn't dissolve in water once it's set. Also, your ball python will drink from any water source whether you want them to or not.

Are you putting in some kind of water fall in the cage?

ya...but I dont think it'll fit its head to be able to drink from it.

Use silicone aquarium sealant. Definately water proof, definately safe to use in a water feature. Should be readily available at your local pet store.

Hot glue is water proof and non toxic. I use it to seal all my cages i build for boas. It holds very well and comes off easy when needed. Will not dissolve in water and it dries fast with no cure time.

You may find hot glue sticky and may start to lift when exposed to a lot of moisture. Hot glue should really only be used for porous materials only, and they don't have to say if the particular brand of glue is safe.
Rhino Glue is 100% food safe and waterproof. Works like magic. I've used it in everything you can think of, even wetsuit repair.