When discussing the rights of service dogs to accompany their owners into the wider world, the ADA is often cited. The Americans with Disabilities Act (ADA) was passed in 1990 by President George H.W. Bush. The goal of the legislation was to prohibit discrimination and ensure equal opportunity for persons with disabilities in employment, State and local government services, public accommodations, commercial facilities, and transportation.
To this end, persons with disabilities are permitted to bring their service animal with them anywhere the general public is allowed. The ADA defines a service animal as any guide dog, signal dog, or other animal individually trained to provide assistance to an individual with a disability. If they meet this definition, animals are considered service animals under the ADA regardless of whether they have been licensed or certified by a state or local government.
Business owners may not insist on proof of state certification before permitting the service animal to accompany the person with a disability. An animal may only be excluded if that animal's behavior poses a direct threat to the health or safety of others.
Not everyone you encounter will be familiar with the ADA. It is helpful to have the text of the law readily accessible on a card you carry, or on your service animal’s ID badge. These products are available at Working Service Dog.