45 C.F.R. § 84.73 – Service animals.

(a) General. Generally, a recipient shall modify its policies, practices, or procedures to permit the use of a service animal by an individual with a disability.
(b) Exceptions. A recipient may ask an individual with a disability to remove a service animal from the premises if—
1. (1) The animal is out of control and the animal's handler does not take effective action to control it; or
2. (2) The animal is not housebroken.
(c) If an animal is properly excluded. If a recipient properly excludes a service animal under paragraph (b) of this section, it shall give the individual with a disability the opportunity to participate in the program or activity without having the service animal on the premises.
(d) Animal under handler's control. A service animal shall be under the control of its handler. A service animal shall have a harness, leash, or other tether, unless either the handler is unable because of a disability to use a harness, leash, or other tether, or the use of a harness, leash, or other tether would interfere with the service animal's safe, effective performance of work or tasks, in which case the service animal must be otherwise under the handler's control (e.g., voice control, signals, or other effective means).
(e) Care or supervision. A recipient is not responsible for the care or supervision of a service animal.
(f) Inquiries. A recipient shall not ask about the nature or extent of a person's disability but may make two inquiries to determine whether an animal qualifies as a service animal. A recipient may ask if the animal is required because of a disability and what work or task the animal has been trained to perform. A recipient shall not require documentation, such as proof that the animal has been certified, trained, or licensed as a service animal. Generally, a recipient may not make these inquiries about a service animal when it is readily apparent that an animal is trained to do work or perform tasks for an individual with a disability (e.g., the dog is observed guiding an individual who is blind or has low vision, pulling a person's wheelchair, or providing assistance with stability or balance to an individual with an observable mobility disability).
(g) Access to areas of the recipient. Individuals with disabilities shall be permitted to be accompanied by their service animals in all areas of the recipient's facilities where members of the public, participants in programs or activities, or invitees, as relevant, are allowed to go.
(h) Surcharges. A recipient shall not ask or require an individual with a disability to pay a surcharge, even if people accompanied by pets are required to pay fees, or to comply with other requirements generally not applicable to people without pets. If a recipient normally charges individuals for the damage they cause, an individual with a disability may be charged for damage caused by their service animal.
(i) Miniature horses—(1) Reasonable modifications. A recipient shall make reasonable modifications in policies, practices, or procedures to permit the use of a miniature horse by an individual with a disability if the miniature horse has been individually trained to do work or perform tasks for the benefit of the individual with a disability.
(2) Assessment factors. In determining whether reasonable modifications in policies, practices, or procedures can be made to allow a miniature horse into a specific facility, a recipient shall consider—
1. (i) The type, size, and weight of the miniature horse and whether the facility can accommodate these features;
2. (ii) Whether the handler has sufficient control of the miniature horse;
3. (iii) Whether the miniature horse is housebroken; and
4. (iv) Whether the miniature horse's presence in a specific facility compromises legitimate safety requirements that are necessary for safe operation.
(3) Other requirements. Paragraphs (c) through (h) of this section, which apply to service animals, shall also apply to miniature horses.