I dont have a lot of time, but the short answer is...not likely. Young babies swim in chlorine filled pools, they get it in their eyes, up their nose, and swollow quite a bit...and they are fine.

Many times, frogs survive a swimming pool without any trouble. And they are soaking in every chemical through their skin.

A snake has less permiable skin than a human, and they have better senses than we do. Therefor, they will not drink water that is not suitable unless they are extremely dehydrated (near death).

If you have a healthy animal, and the chlorine levels in the pool are a tad on the lower side (the pool was not recently "shocked", I would not worry about it at all.

As an example: I certainly worry about the room being ventalated well if I clean with any effective bleach solution. I even worry a bit with higher concentrations of chlorohexadine. If I have a little bug spray on my hands and forget about it when I catch a frog, I quickly rush it to fresh water and I worry a lot about its health. But I do not worry about a 7ft anaconda swimming in a swimming pool treated with chlorine to keep bacteria growth down. I would certainly not allow the snake to swim in untreated water.

I hope that helps