Pet Insurance Pre-Existing Conditions: Curable vs Incurable, and What the Insurer Has to Prove
The claim comes back denied: pre-existing condition. Maybe your dog limped once before you bought the policy, or the vet noted an ear infection two years ago. Whether that denial holds depends on how the policy defines pre-existing, whether the condition is curable, and which state you live in. This guide is part of our pet insurance guide.
Key takeaways
- Under the NAIC model definition, a condition is pre-existing if, before coverage began or during a waiting period, a vet gave advice, the pet was treated, or the pet had related signs or symptoms.
- In states that adopted the model, the insurer "has the burden of proving that the preexisting condition exclusion applies."
- A condition your policy covered cannot be relabeled pre-existing when the same policy renews.
- Curable and incurable conditions are often treated differently. Illinois regulators describe policies that cover a cured condition after it has been "treatment-free for at least six months." That is a policy feature, not a legal requirement.
- Chronic conditions, defined as treatable or manageable but not curable, can be excluded with disclosure, and a cured-condition clause does not reach them.
What counts as a pre-existing condition for pet insurance?
The NAIC Pet Insurance Model Act, adopted in 2022, defines it as any condition for which any of the following were true before the policy's effective date or during any waiting period:
- "A veterinarian provided medical advice;"
- "The pet received previous treatment; or"
- "Based on information from verifiable sources, the pet had signs or symptoms directly related to the condition for which a claim is being made."
Note the third prong. A formal diagnosis is not required. Symptoms recorded anywhere verifiable, including notes from an earlier vet visit, can be enough.
The model also says: "A condition for which coverage is afforded on a policy cannot be considered a preexisting condition on any renewal of the policy." NAIC's project history explains why regulators added it: they wanted to stop a covered condition from becoming excluded on renewal.
Washington's pet insurance law, RCW 48.205, adopts these definitions nearly word for word.
What is the difference between curable and incurable pre-existing conditions?
The model act itself does not create a curable exception. Insurers decide whether to offer one, and state regulators describe how it usually works.
The Illinois Department of Insurance tells shoppers to "look to see if your pet's condition is considered curable (stable or controlled pre-existing conditions) or incurable (terminal pre-existing conditions)." It says that for curable conditions, "the company may choose to enforce a waiting period before coverage kicks in," while conditions "considered incurable such as diabetes or cancer may be excluded entirely or may be covered on a limited basis." It adds that "a company may also provide coverage for temporary conditions that are proven to have been cured and treatment-free for at least six months."
The NAIC's consumer guidance uses the same curable and incurable language. Forbes Advisor reports that at least one insurer requires a pet to be symptom- and treatment-free for 12 months before covering a curable pre-existing condition.
| Condition type | Example (from regulators) | How policies often treat it | Legal definition in model states |
|---|---|---|---|
| Curable, resolved | A temporary condition proven cured | May be covered after a symptom- and treatment-free period (Illinois cites at least six months; Forbes Advisor reports 12 months at one insurer), if the policy allows | Still meets the pre-existing definition; coverage depends on policy terms |
| Incurable | Diabetes, cancer | Excluded entirely or covered on a limited basis | Pre-existing if it meets the three-prong test |
| Chronic | Allergies, osteoarthritis (Illinois calls these ongoing conditions) | Usually excluded if present before coverage; check continuous-coverage terms | "A condition that can be treated or managed, but not cured" |
| Hereditary or congenital | Hip dysplasia in breeds prone to it (Triple-I example) | Often excluded or limited; must be disclosed | Hereditary: "genetically transmitted from parent to offspring" |
Sources: Illinois Department of Insurance, NAIC model act and consumer guidance, Triple-I, Forbes Advisor, accessed October 1, 2026.
Which states adopted the NAIC Pet Insurance Model Act?
NAIC's state adoption chart lists these states as having adopted the model "in a substantially similar manner":
| State | Citation (per NAIC) |
|---|---|
| California | Cal. Ins. Code §§ 12880.0 to 12880.6 |
| Delaware | Del. Code tit. 18, §§ 8801 to 8809 |
| Florida | Fla. Stat. § 627.71545 |
| Hawaii | Haw. Rev. Stat. §§ 431:33-101 to 431:33-109 |
| Louisiana | La. Stat. §§ 22:1371 to 22:1375 |
| Maine | Me. Rev. Stat. tit. 24-A, §§ 3151 to 3161 |
| Maryland | Md. Code, Ins. §§ 19-1101 to 19-1107 |
| Mississippi | Miss. Code §§ 83-87-1 to 83-87-9 |
| Montana | Mont. Code §§ 33-24-401 to 33-24-409 |
| Nebraska | Neb. Rev. Stat. §§ 44-6501 to 44-6510 |
| New Hampshire | N.H. Rev. Stat. §§ 402-P:1 to 402-P:6 |
| New Jersey | N.J. Stat. §§ 17:46D-3 to 17:46D-8 (effective January 1, 2027) |
| Ohio | Ohio Rev. Code §§ 3970.01 to 3970.08 |
| Pennsylvania | 40 Pa. Stat. §§ 4701 to 4711 |
| Rhode Island | R.I. Gen. Laws §§ 27-83-1 to 27-83-7 |
| Vermont | Vt. Stat. tit. 8, §§ 7151 to 7159 |
| Washington | Wash. Rev. Code §§ 48.205.010 to 48.205.080 |
Source: NAIC, Pet Insurance Model Act state page, accessed October 1, 2026. NAIC notes the chart "does not constitute a formal legal opinion" and readers "should consult state law."
If your state is not on the list, your protections come from your policy and your state's general insurance law. You can still ask your state insurance department for help with a denial.
What does the insurer have to prove?
In model-law states, two rules matter most at claim time.
First, the burden of proof. The model says the insurer "may issue policies that exclude coverage on the basis of one or more preexisting conditions with appropriate disclosure," but "the pet insurer has the burden of proving that the preexisting condition exclusion applies to the condition for which a claim is being made." Forbes Advisor describes the practical effect: the insurer, not you, has to produce the evidence.
Second, disclosure. Insurers must tell you up front if the policy excludes pre-existing, hereditary, congenital or chronic conditions, and must list them in an "Insurer Disclosure of Important Policy Provisions" document.
If a claim is denied: Ask the insurer in writing which records it relied on and which of the three prongs it says applies. In a model-law state, the insurer carries the burden. If you disagree, contact your state insurance department; Illinois, for example, publishes a complaint process on its site.
Can a vet exam at enrollment hurt you?
It can. The model act says that if a vet exam is required to start coverage, the insurer must disclose "that examination documentation may result in a preexisting condition exclusion." Anything the vet notes during that exam is a record from before or during the waiting period. Book it knowing that.
What about conditions that start after you buy?
Those are not pre-existing, as long as they first appear after the policy starts and after any waiting period ends. Timing matters. Our guide to pet insurance waiting periods explains why a symptom that appears in week two can still be excluded.
Illinois also flags ongoing conditions that run past a policy year, such as allergies and osteoarthritis. It warns that "some companies consider conditions treated during a previous policy term to be pre-existing (even if you are staying with the same plan)." In model-law states, a condition covered under your policy cannot be treated as pre-existing at renewal; elsewhere, check for continuous-coverage terms.
For an older dog with a long vet history, pre-existing rules shape the whole decision. See is pet insurance worth it for a senior dog.
Frequently asked questions
Does any pet insurance cover pre-existing conditions?
Some policies cover curable pre-existing conditions after a symptom- and treatment-free period, per Illinois regulators and Forbes Advisor. Incurable conditions such as diabetes or cancer "may be excluded entirely or may be covered on a limited basis," per Illinois.
Does the NAIC model law require insurers to cover curable conditions?
No. The model allows insurers to exclude pre-existing conditions with disclosure. What it adds is that the insurer must prove the exclusion applies, and that a covered condition cannot become pre-existing at renewal.
Is a hereditary condition pre-existing?
It is pre-existing only if it meets the definition, but policies may exclude hereditary or congenital conditions separately. Illinois says "most pet insurance companies consider genetic conditions to be pre-existing and do not cover them." Model-law insurers must disclose such exclusions.
If I switch pet insurers, do current conditions become pre-existing?
Usually yes for the new insurer, because they existed before its policy began. The renewal protection applies only to renewals with the same or an affiliated insurer.
How long is the symptom-free period for a curable condition?
It depends on the policy. Illinois describes "at least six months," and Forbes Advisor reports 12 months at one insurer. Read the definition in your policy.
Sources
- NAIC, "Pet Insurance Model Act" (MO-633), https://content.naic.org/sites/default/files/model-law-633.pdf, accessed October 1, 2026.
- NAIC, "Project History: 2022 Pet Insurance Model Act (#633)," https://content.naic.org/sites/default/files/model-law-project-history-633.pdf, accessed October 1, 2026.
- NAIC, Pet Insurance Model Act state page (ST-633), https://content.naic.org/sites/default/files/model-law-state-page-633_1.pdf, accessed October 1, 2026.
- NAIC, "Pet Insurance: It Could Save Your Pet's Life, Could Save You Money," https://content.naic.org/article/consumer-insight-pet-insurance-it-could-save-your-pets-life-could-save-you-money, accessed October 1, 2026.
- Washington State Legislature, Chapter 48.205 RCW, https://app.leg.wa.gov/RCW/default.aspx?cite=48.205&full=true, accessed October 1, 2026.
- Illinois Department of Insurance, "Pet Health Insurance," https://idoi.illinois.gov/consumers/consumerinsurance/pets.html, accessed October 1, 2026.
- Insurance Information Institute, "Facts about pet insurance," https://www.iii.org/article/facts-about-pet-insurance, accessed October 1, 2026.
- Forbes Advisor, "New State Rules Aim To Limit Surprise Pet Insurance Preexisting Condition Denials," https://www.forbes.com/advisor/pet-insurance/state-rules-limit-pet-insurance-denials-lmandp5/, accessed October 1, 2026.
Pet insurance laws differ by state, and policies differ by insurer. Everything above is quoted from the source cited, as accessed on October 1, 2026. This is general information, not legal advice.