I would like to reiterate what Doug said concerning the potential for hazard with Hydrodynastes. They will reach breeding age & size at two years. They will continue to grow after that. At five years, your snake may well be over seven feet and nearly as thick as your wrist. Luckily, most calm down in regards to humans after the first six months or so. They are, however, not to be trusted & are always a threat to bite at feeding time.
There is a paper out there studying the venom which makes the case that the venom is about the same strength as Crotalus atrox, the western diamondback rattlesnake. Admittedly, the venom delivery system is not that good because they are opistoglyphs, but there is no antivenin for them either.
I raised several generations of these animals over a thirteen year period.
You say that was a rescue animal. Was it an escapee, or did the owner just not want it?
~~Greg~~