The dog does not eat and only drinks water because it may be picky eaters, the dog food does not suit the taste, or it is caused by illness. You need to observe the dog's condition first to see if there is any abnormality. If there is any abnormality, send it to the hospital for examination and treatment in time. If it is caused by picky eating, you can improve the dog's diet. Do not let the dog only eat dog food all the time, which can easily lead to anorexia in the dog.