An Esa is not the same as a service animal.. there is 2 questions someone can ask..

Q7. What questions can a covered entity's employees ask to determine if a dog is a service animal?

A. In situations where it is not obvious that the dog is a service animal, staff may ask only two specific questions: (1) is the dog a service animal required because of a disability? and (2) what work or task has the dog been trained to perform? Staff are not allowed to request any documentation for the dog, require that the dog demonstrate its task, or inquire about the nature of the person's disability.

Q17. Does the ADA require that service animals be certified as service animals?

A. No.  Covered entities may not require documentation, such as proof that the animal has been certified, trained, or licensed as a service animal, as a condition for entry.

Q35. Do apartments, mobile home parks, and other residential properties have to comply with the ADA?

A. The ADA applies to housing programs administered by state and local governments, such as public housing authorities, and by places of public accommodation, such as public and private universities.  In addition, the Fair Housing Act applies to virtually all types of housing, both public and privately-owned, including housing covered by the ADA.  Under the Fair Housing Act, housing providers are obligated to permit, as a reasonable accommodation, the use of animals that work, provide assistance, or perform tasks that benefit persons with a disabilities, or provide emotional support to alleviate a symptom or effect of a disability.  For information about these Fair Housing Act requirements see HUD’s Notice on Service Animals and Assistance Animals for People with Disabilities in Housing and HUD-funded Programs.

Here ya go from the ADA themselves