On September 15th, 2010, the federal government issued a clarified statement about what a service dog is and isn't. The specific wording is:

Service animals are defined as dogs that are individually trained to do work or perform tasks for people with disabilities.

Each of the above terms are strictly defined. For instance:

• "People with disabilities" aren't just anyone, they're people who are quite disabled, and are defined as “unable to perform a major life activity that the average person in the general population can perform,”
  • A “major life activity” is then defined, too, as “functions such as caring for oneself, performing manual tasks, walking, seeing, hearing, speaking, breathing, learning, and working.” (“The Americans with Disabilities Act: The New Definition of Disability Post: Sutton v. United Air Lines, Inc.” in Marquette Law Review, Christine M. Harrington, Fall 2000.)
• While "tasks" are not specifically defined, there are examples given, which are "guiding people who are blind, alerting people who are deaf, pulling a wheelchair, alerting and protecting a person who is having a seizure, reminding a person with mental illness to take prescribed medications, calming a person with Post Traumatic Stress Disorder (PTSD) during an anxiety attack".
• The law notes that the tasks must be directly related to the person's disability.

What can service dogs do?

The law goes into where the dog and handler can go, which is defined as "where the public is normally allowed to go".

What restrictions are on service dogs?

In general, the dog must be leashed. Other requirements are that the dog is in control, and that the dog is housebroken.

Questions about the dog and disability:

The law also goes into what a staff person can ask about the dog, which are two questions - one is to confirm that the dog is required because of a disability, and the other is to ask what task the dog performs.