The following text is from the Judge David L. Bazelon Center for Mental Health Law. I checked with my local fair housing council (the people to whom one reports violations) when I used this letter and they agreed the last paragraph is not necessary. You may want to omit it because it allows the landlord to impose on your provider’s time and they may charge you for it or be reluctant to sign the letter with it included.

Note that you do NOT need a psychiatrist or a psychologist to sign the letter. Also a dog you intend to train as a psych service dog can be an emotional support dog until they meet the definition of a service dog.

Sample Letter from a Service Provider

[date]

Name of Professional (therapist, physician, psychiatrist, rehabilitation counselor)

XXX Road City,

State Zip

Dear [Housing Authority/Landlord]:

[Full Name of Tenant] is my patient, and has been under my care since [date]. I am intimately familiar with his/her history and with the functional limitations imposed by his/her disability. He/She meets the definition of disability under the Americans with Disabilities Act, the Fair Housing Act, and the Rehabilitation Act of 1973. Due to mental illness, [first name] has certain limitations regarding [social interaction/coping with stress/ anxiety, etc.]. In order to help alleviate these difficulties, and to enhance his/her ability to live independently and to fully use and enjoy the dwelling unit you own and/or administer, I am prescribing an emotional support animal that will assist [first name] in coping with his/her disability.

I am familiar with the voluminous professional literature concerning the therapeutic benefits of assistance animals for people with disabilities such as that experienced by [first name]. Upon request, I will share citations to relevant studies, and would be happy to answer other questions you may have concerning my recommendation that [Full Name of Tenant] have an emotional support animal Should you have additional questions, please do not hesitate to contact me.

Sincerely, Name of Professional

[emphasis (strikethrough) added]
http://www.bazelon.org/wp-content/uploads/2017/04/2017-06-16-Emotional-Support-Animal-Fact-Sheet-for-Website-final.pdf