Water snakes in the south are considered poisonous until proven otherwise. I personally have never had a situation where I felt threatened but have had some close encounters. My late friend Pete White was no wimp, BAR man 82nd Airborne, WWII, 2 Purple Hearts. He told me years ago of crappie fishing with minnows on Wilson Lake of the TN River when a cottonmouth dropped into his aluminum semi-vee boat. He said, "I was 12 to 15 ft. off the bank and the next thing I knew I was standing there one the bank. Don't know how I got there, my feet weren't wet." But cottonmouths are nasty tempered, dangerous snakes who will not move out of your way. I had two swimming to the point I was standing on casting, when they got there I was gone as I did not have a proper weapon with me.