Look at the stomach plates, Are they a single row or split into dual rows. Also your sure no fangs? When a snake is dead the fangs often tuck into thier recesses, you may have to pull them out of their folds. Split row stomach scales are normally an indicator of a venomous snake.
From head it looks nonvenomous but it's hard to tell with the Conan grip you have on it..LOL
After some research I think it might be an Everglades Rat Snake. I don't think I'll ever know for sure since the chlorine in the pool may have bleached the color a bit. I don't like killing them unless they're poisonous but this one I've never seen here and was worried about my dogs getting bit.
It would be smart to have an anti-venom kit if there are a good amount of poisenous snakes in your area. Snake venom has to be one of the worst things to die from IMO. I've seen pics of what happens to people with snake bites and it looks like a realy shitty way to go. They're not even recognizable 6-7 hours after the bite.