By deep water I mean anything deeper than eight to 12 feet. I say big bass. There are always some fish shallow, and if there is a lot of structure or hiding places available some big bass may be shallow. But every fisheries biologist you talk to will tell you that after the spawn a big bass will not move one foot more than she has to, to eat. So after the two or three months of the year when she moves shallow to spawn, her home is in deep water.
Deep water means different things in different places.
In Florida, where the deepest water in the lake is 10 to 20 feet, this is where she will be. But in California, Arizona, New Mexico and some parts of Texas, deep water could be 60 or 70 feet or even 90 feet or more in depth. You next have to realize that fish move around and through a body of water using the same set of highways every day. That may be a creek channel , a break line , or a weed line that extends out into deep water. The key part of all this thinking is where the fish move toward the depth where they feed.