I don't think Copperheads and Water Moccassins are related, other than both being pit vipers. Cottonmouth Moccassins are a type of Water Moccassin with white or light colored insides of their mouths. When they open their mouths to hiss at you, their open mouth is in stark contrast to the black body. After you have been around Moccassins for a while, you can usually tell when one is near, they have a distinct smell to them that is very strong. They also have an ugly disposition, and are not prone to running away, they prefer to hiss and strike. Also, they don't have to be coiled to strike like a Rattlesnake, they can strike from any position either in or out of the water.
