Real freshwater bodies are less common than saltwater bodies. Most of the water on our planet contains a certain amount of salt in it, which means it is not pure freshwater. The amount of saltwater is substantial compared to freshwater, and the salts found in saltwater are different than the salt that is used for cooking. The water is comprised of many components that break down, and they become electrically charged ions.
The particles in the water are electrical conductors, which can be found flowing through saltwater. It is not a good idea to drink seawater, as It could dehydrate you worse than if you drank no water at all. Much of the aquatic wildlife cannot survive in both types of water. For example, taking a fish out of freshwater and leaving it in saltwater, it will not survive.