I ran commercial swimming pools for a few years (neighborhood pools, country club pools, etc) and we'd have that happen a few times every year. The staff - in most cases - would get the people out of the pool, then wait for me to come get it out. Even if it took an hour for me to get there, LOL.
Most of the snakes that were in the pools were small, usually under 12", and I'd just net them out. I'd get an old drink cup out of the truck, put the snake in the cup, and release it in an unpopulated area on my travels. I really hate to kill something if I don't have to.
I did have a guard find a 6' copperhead in the pool he worked at - he took the big shepherd's hook that was at the facility, hooked the snake, and tossed it back into the neighboring wetland area that it probably came from. He was the only one who took care of a snake himself! Even I'm pretty sure I wouldn't have tried to get one that size out, I'd probably have called animal control - or my boss!