Most people do not know there is a differnce. People need to know that therapy dogs have no more rights than other pet dogs they can be refused from any building at anytime and it is not against the law, but assitance dogs have to be let in no matter what
Therapy Dogs are not Service Dogs
Most of this page is about therapy dogs. The most important piece of information you need to know about therapy dogs, though, is what they are not. Therapy dogs are not service (or "assistance") dogs.
Why does this matter? Well, because service dogs are vitally important to those people with disabilities who are fortunate enough to have these wonderful animals. Service dogs include guide (or "leader") dogs for the blind; hearing dogs, that alert their owners to sounds; mobility assistance dogs, which may pull a wheelchair or directly support a person; seizure alert dogs; and others. Under the Americans with Disabilities Act, a person with a disability is entitled to take a service animal with him, or her, wherever it is needed. Period. You can read more about service dogs at the sites listed below.
The exact language of the ADA that covers service dogs, borrowed from a now defunct service-and-therapy-dog web site, follows here:
Service Animal means any guide dog, signal dog or other animal individually trained to do work or perform tasks for the benefit of an individual with a disability, including but not limited to guiding individuals with impaired vision, alerting individuals with impaired hearing to intruders, providing minimal rescue or protection work, pulling a wheelchair or fetching dropped items.
Therapy dogs, on the other hand, perform their tasks by invitation. The owner of a therapy dog has no more "right" of access to a hospital, nursing home, or public place than any other able-bodied person with a pet. (Note that the "right" accrues to the person, in either case, not to the dog! This is a crucial distinction that many fail to make.) As you will see in Professor Hunt's Virtual Lecture on Therapy Dogs, below, most hospitals and some nursing homes require a lot of paperwork before a therapy dog sets foot in the facility--the same facility where any person with a disability has a clear right to enter with his or her service dog.