^^^^^^^^^^ Indeed they do. The largest water snake I've seen in my lifetime was a diamond-backed water snake. In both length and girth....it was HUGE. Sunning itself on a large piece of foam dock flotation material on Lake Travis.
As it uncoiled itself and slipped into the water I got a really good look at it. I'm guessing it was all of 5 feet long (or better) and probably 8" in girth. Big...powerful snake.
I've caught small ones while wading creeks, but you have to catch them on land, they are much too fast in the water.
And YES, they are all too happy to BITE...if they see an opportunity.