Take your time to slowly get him back to the water. It will probably take some time now. They are water dogs so eventually he will come around. After you notice he has confidence you, try going in the water first. By him seeing you in there might help. You are like a parent him now. He might just go out with one paw, then two…eventually he will go in again. It will probably be only on his terms. Bring him around water often. He might not always go in but start by letting him see it isn’t bad.