To answer these and other questions, first we have to address a few definitions. Under the Americans with Disabilities Act of 1990 (ADA), the Department of Justice's Civil Rights Division defines a "service animal" as "any dog that is individually trained to do work or perform tasks for the benefit of an individual with a disability." Note that under this definition a service animal can only be a dog. Also, the dog's work or task "must be directly related to the individual's disability...The crime deterrent effects of an animal's presence and the provision of emotional support, well-being, comfort, or companionship do not constitute work or tasks for the purposes of this definition." A service dog can be any breed.
Separate from the ADA, a landlord must also consider the Fair Housing Act (FHA) which addresses assistance animals. Assistance animals are more broadly defined than service dogs. According to the Dept. of Housing and Urban Development (HUD) an assistance animal is "not a pet" but instead an animal "that works, provides assistance, or performs tasks for the benefit of a person with a disability, or provides emotional support that alleviates one or more identified symptoms or effects of a person's disability." An assistance animal does not have to be a dog and is not required to have specialized training.
The first question a landlord should ask is whether the tenant has a service dog or an assistance animal (see above for the difference). This is important because the additional questions that may be ask depend on the type of service the animal offers.
A landlord is only permitted to ask two questions of someone claiming to have a service dog: #1 Is the service dog required because of a disability? #2 What work or task has the dog been trained to perform?
A landlord is permitted to ask two questions of someone claiming to have an assistance animal: #1 Does the animal's owner have a disability (a physical or mental impairment that substantially limits one or more major life activity)? #2 Does the animal's owner have a disability-related need for an assistance animal? Note that unlike service dogs, an assistance animal does not have to have any training.
Under the FHA a landlord may ask for proof of the person's need for an assistance animal, unless the disability is obvious. This can include a letter from a physician stating that the tenant has a disability and the assistance animal will provide some disability-related assistance.
Under the ADA a landlord may not ask for proof of the owner's disability. A landlord may not require proof of the service dog's training, and may not require professional training. A service dog does not have to wear a vest.
A service dog or ESA must be leashed in public areas, cannot be out of control, and must be housebroken. If there is a legitimate safety concern the service dog or ESA may be excluded from parts of the building. For example, if another tenant is allergic to animals the service dog may be excluded from that area. The animal may be required to relieve itself only in specific areas with the owner responsible for clean-up. Any refusal to allow a service dog or assistance animal should only be used on a case-by-case basis and not premised on stereotypes about, for example, a dog's breed.
There appears to be no prohibition requiring the tenant to indemnify the landlord for damages or injuries by the animal.
No. While a pet fee cannot be charged, the animal's owner may be charged for damage to the premises as well as any additional cleaning costs such as for pet hair, pet waste, or excess damage.