Writing an emotional support animal (ESA) letter requires you to document a client’s disability-related need for an animal in a way that satisfies federal housing law while protecting your clinical and legal standing. The letter itself is straightforward, but the process around it, including your relationship with the client, what you can and cannot include, and how state laws shape your obligations, matters just as much as the words on the page.
What Federal Law Actually Requires
HUD’s guidance on assistance animals does not require ESA documentation to follow a specific format. There is no official template or government form. What HUD does require is that the letter come from a licensed health care professional who has personal knowledge of the individual and can confirm two things: that the person has a disability affecting a major life activity, and that they have a related need for an assistance animal for therapeutic purposes.
That phrase, “personal knowledge,” is doing a lot of work. HUD has made clear that certificates purchased from websites where someone answers a few questions, does a brief interview, and pays a fee are not considered reliable evidence of a disability or disability-related need. In HUD’s own words, “such certificates are not meaningful and a waste of money.” This means your letter carries weight precisely because you have an established therapeutic relationship with the client. Telehealth is fine, as HUD acknowledges that documentation from legitimate, licensed professionals delivering services remotely can be reliable, but a real clinical relationship must exist.
What to Include in the Letter
Keep the letter concise and professional. A solid ESA letter typically runs one page and includes these elements:
- Your credentials: Full name, license type, license number, the state where you’re licensed, and the effective date of your license.
- Confirmation of the therapeutic relationship: A statement that the client is currently under your care, without specifying a diagnosis unless necessary. You do not need to disclose the full nature of treatment.
- Statement of disability: Language confirming the individual has a mental health condition that substantially limits one or more major life activities. You do not need to name the specific diagnosis for a housing provider.
- Therapeutic need for the animal: A clear statement that the emotional support animal is part of the client’s treatment plan or provides disability-related therapeutic benefit.
- Date and signature: The date of issuance and your professional signature.
You are not required to describe the animal’s breed, size, or training. You are not required to explain your treatment plan in detail. Housing providers can ask for documentation of a disability-related need, but they cannot demand your clinical notes, a specific diagnosis, or details about the client’s treatment history. Keeping the letter focused on what the law requires protects your client’s privacy.
The Clinical Evaluation Behind the Letter
The letter is just the output. What supports it is your clinical judgment that the client genuinely has a condition that rises to the level of a disability and that an emotional support animal provides a meaningful therapeutic benefit. This is a clinical determination, not a favor to a client who likes their pet.
Before writing the letter, assess whether the client’s condition substantially limits a major life activity such as sleeping, concentrating, maintaining social relationships, or daily functioning. Then determine whether the presence of the animal has a documented or clinically reasonable connection to alleviating symptoms of that condition. If a client asks for a letter and you are not confident the clinical basis exists, you are under no obligation to write one. As one malpractice insurer advises, you can let the client know you’re willing to write a letter that is “accurate, truthful, and clinically supportable,” but you should not state that a client has a mental health condition unless you are confident of its existence.
If a client you’ve only seen once or twice asks for an ESA letter, consider whether you have enough clinical information to make this determination responsibly. Some states have formalized this concern into law.
State Laws That Add Requirements
Federal law sets the floor, but several states have passed legislation that adds specific obligations for therapists writing ESA letters. California’s AB 468, which took effect in 2022, is one of the most detailed examples and a useful benchmark even if you practice elsewhere.
Under California law, if you’re providing documentation for an emotional support dog, you must meet all of the following conditions:
- Hold a valid, active license and include your license number, jurisdiction, license type, and effective date in the documentation.
- Be licensed in the jurisdiction where the client is located.
- Have an established client-provider relationship for at least 30 days before issuing the letter.
- Complete a clinical evaluation of the individual’s need for the animal.
- Provide a verbal or written notice that fraudulently representing oneself as the owner of a service dog is a misdemeanor.
The California Board of Behavioral Sciences has clarified that the 30-day requirement refers to the length of the relationship, not a specific number of sessions. Other states, including Florida, Virginia, and New York, have enacted or proposed similar legislation targeting ESA letter mills. Check your own state licensing board for any specific rules that apply to you, as this area of law has been changing rapidly.
Protecting Yourself From Liability
Writing an ESA letter is a clinical act that carries liability. You are putting your professional judgment on paper, and that document may be scrutinized by a housing provider, a landlord’s attorney, or in rare cases, a licensing board.
The biggest risk is writing a letter for someone who does not meet the clinical threshold. If a client is requesting a letter as a workaround for a no-pets policy and does not have a qualifying condition, issuing the letter exposes you to complaints of fraud or ethical violations. Be direct with clients when this is the case. You can explain that the letter needs to reflect your honest clinical assessment and that an inaccurate letter could create legal problems for both of you.
Document your clinical reasoning in the client’s chart. Note the assessment you conducted, the basis for your determination, and the fact that you discussed the purpose and limitations of the letter with the client. This protects you if the letter is ever questioned. Keep a copy of the letter itself in the client’s file.
Renewals and Expiration Dates
HUD does not specify a required validity period for ESA letters, and there is no federal rule that letters expire after one year. In practice, however, most housing providers expect a letter dated within the past 12 months, and many will request updated documentation at lease renewal. Writing a letter with a date gives the housing provider a reference point and gives you a natural interval for reassessment.
When a client returns for a renewal letter, treat it as a clinical check-in rather than a rubber stamp. Confirm that the condition still meets the threshold of a disability, that the animal continues to provide therapeutic benefit, and that nothing has changed that would alter your assessment. A brief note in the chart documenting this reassessment is sufficient.
Handling Requests From Non-Clients
You will occasionally get calls from people who are not your clients asking if you can write them an ESA letter. This is exactly the scenario that HUD, state legislatures, and licensing boards have been cracking down on. There is no official ESA registry, and any website claiming to “register” an animal or provide a certificate as proof of ESA status is misleading.
If someone contacts you specifically for an ESA letter, you can take them on as a client and conduct a proper evaluation over the course of your state’s required relationship period. What you should not do is conduct a single brief interview and issue a letter on the spot. That model is what HUD has flagged as unreliable, and it is what state laws like California’s AB 468 were written to prevent. Your credibility as a provider, and the enforceability of the letters you write, depends on the clinical relationship behind them.