The U.S. Department of Housing and Urban Development requires housing providers to make an exception to a "no pet" rule if:

• an individual living with an animal has a disability which significantly impairs one or more major life activities
• the animal must provide relief related to the identified disability

This can require verification from a mental health professional or doctor.

Landlords can't:

• require tenants to pay fees for ESA's
• Ask for information regarding the person's disability, or ask for extensive medical records
• refuse to accommodate an ESA or require it to have training.