COMPANION DOG – Trained Pet Dog.  EMOTIONAL SUPP0ORT DOG -Well trained Pet dog.  They DO NOT Have not access rights except under the Fair Housing Act.  THERAPY DOG:  are dogs that are trained to give comfort to individuals, that you take to visit in places like hospitals, nursing homes, etc.  They do not have access rights except where they are visiting.   SERVICE DOG: are dogs that are task trained to assist with/mitigate a disability.  They have access rights.