Service animals are defined as dogs that are individually trained to do work or perform tasks for people with disabilities
Examples of such work or tasks include 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, or performing other duties. Service animals are working animals, not pets. The work or task a dog has been trained to provide must be directly related to the person's disability. Dogs whose sole function is to provide comfort or emotional support do not qualify as service animals under the ADA.
Under the Americans with Disabilities Act (ADA), businesses and organizations that serve the public must allow people with disabilities to bring their service animals into all areas of the facility where customers are normally allowed to go. This federal law applies to all businesses open to the public, including restaurants, hotels, taxis and shuttles, grocery and department stores, hospitals and medical offices, theaters, health clubs, parks, and zoos.
Service Animals and Emotional Support Animals, ADA National Network
Service Animals and Emotional Support Animals, ADA National Network (PDF)