The IRS does not audit every HSA withdrawal, but it runs an automatic check on all of them. Your HSA custodian reports every dollar leaving the account on Form 1099-SA, and you tell the IRS on Form 8889 how much of that went to qualified medical expenses. When those two numbers don’t line up, the return gets flagged. Even when they do line up, a large tax-free distribution or certain categories of spending can prompt the agency to ask for receipts, and the burden of proving each expense was medical sits entirely on you.
How the IRS Sees Your HSA Activity
Two forms create the paper trail. Your custodian files Form 1099-SA with the IRS and sends you a copy. Box 1 reports the gross amount distributed; Box 3 carries a code identifying the type of distribution.1Internal Revenue Service. Instructions for Forms 1099-SA and 5498-SA The custodian has no idea what you spent the money on. They just report the total that came out.
You then file Form 8889 with your return. Line 14a captures the total distribution from the 1099-SA. Line 15 is where you enter the amount spent on qualified medical expenses.2Internal Revenue Service. Instructions for Form 8889 The difference between the two lines is what gets taxed. If they match, you owe nothing. If distributions exceed qualified expenses, the gap becomes taxable income with a penalty on top.
The IRS receives both documents independently. The 1099-SA tells the agency what came out of the account. Form 8889 tells them what you claim it was for. That side-by-side comparison is the primary audit mechanism for HSA withdrawals, and it runs on every return without a human reviewer having to open the file.
What Triggers IRS Scrutiny
The clearest trigger is a mismatch. If your 1099-SA shows $15,000 in distributions and your Form 8889 claims $5,000 in qualified expenses, the IRS sees $10,000 in taxable income and a $2,000 penalty. Gaps that size reliably generate a notice.
A large distribution reported as entirely tax-free raises a different kind of flag. The IRS uses automated screening that looks for improbable patterns across returns. Claiming $25,000 in tax-free medical spending when your income and filing history suggest otherwise is the kind of outlier the screening is built to catch.
Specific expense categories attract closer attention because they sit at the edge of the rules. Long-term care insurance premiums, Medicare premium payments from an HSA, and COBRA coverage costs all require detailed substantiation. They’re exceptions to the general rule that insurance premiums don’t qualify, so the IRS looks harder at them.3Internal Revenue Service. Publication 969 – Health Savings Accounts and Other Tax-Favored Health Plans
Not filing Form 8889 at all is probably the fastest way to hear from the IRS. If a 1099-SA arrives at the agency with no Form 8889 on your return, the system treats the entire distribution as taxable and sends a notice for the full tax plus the 20% penalty.
What You’ll Have to Prove
If the IRS questions a distribution, you have to show the money went to a qualified medical expense. Federal law defines that by reference to the tax code’s definition of medical care: amounts paid for the diagnosis, cure, treatment, or prevention of disease, or for treatment affecting any structure or function of the body.4Office of the Law Revision Counsel. 26 U.S. Code 223 – Health Savings Accounts IRS Publication 502 lists what falls inside and outside that definition.5Internal Revenue Service. Publication 502 – Medical and Dental Expenses The expense must be yours, your spouse’s, or a dependent’s, and it must have been incurred after you established the HSA.
Common qualifying costs include deductibles, copayments, prescription drugs, dental work, vision care, and medical equipment like crutches or blood-sugar monitors. Menstrual care products also qualify. The exclusions catch people more often than the inclusions. Vitamins, supplements, and gym memberships don’t count unless a physician diagnoses a specific condition and prescribes them as treatment. Cosmetic procedures don’t qualify unless they address a deformity from a congenital condition, injury, or disease. Insurance premiums generally don’t qualify either, with narrow exceptions for COBRA, long-term care, coverage while collecting unemployment, and Medicare Parts A, B, and D after age 65 (Medigap is still excluded).
Documentation That Actually Works
A bank statement or credit card receipt isn’t enough. Those show that money changed hands, not what it was for. The strongest documentation pairs the provider’s itemized invoice (describing the service and the amount charged) with the Explanation of Benefits from your insurance company (showing what was covered, what applied to your deductible, and what you owed). Together, they prove both that the expense was medical and that you were actually responsible for the amount paid.
Publication 969 requires records showing three things: distributions went only toward qualified medical expenses, those expenses weren’t reimbursed from another source, and you didn’t claim them as an itemized deduction in any year.3Internal Revenue Service. Publication 969 – Health Savings Accounts and Other Tax-Favored Health Plans
What a Non-Qualified Withdrawal Costs
Using HSA money for something that isn’t a qualified medical expense triggers two charges. The non-qualified amount gets added to your gross income for the year and taxed at your ordinary rate.4Office of the Law Revision Counsel. 26 U.S. Code 223 – Health Savings Accounts On top of that, you owe an additional 20% tax.2Internal Revenue Service. Instructions for Form 8889 On a $1,000 non-qualified withdrawal, that’s $1,000 added to taxable income plus a $200 penalty. In the 22% bracket, the total hit comes to $420 on $1,000. The 20% penalty is calculated on Line 17b of Form 8889 and flows through to Schedule 2 of your Form 1040.6Internal Revenue Service. Form 8889 – Health Savings Accounts
Three situations eliminate the 20% additional tax, though the income tax still applies. Reaching age 65 ends the penalty, which is why some people treat the account as a backup retirement vehicle after Medicare eligibility. Becoming disabled under the tax code’s definition waives it. Distributions from a deceased account holder’s HSA are also exempt from the penalty.
Fixing a Mistaken Withdrawal Before It Becomes an Audit Problem
If you took a distribution thinking an expense was qualified and later found out it wasn’t, you can return the money to the HSA and undo the tax consequences. The IRS calls this a mistaken distribution. The deadline for returning it is the due date of your tax return, without extensions, for the first year you knew or should have known the distribution was a mistake.1Internal Revenue Service. Instructions for Forms 1099-SA and 5498-SA For most people that’s April 15 of the following year.
When you return the funds properly, the distribution stays out of gross income, the 20% tax doesn’t apply, and the repayment isn’t counted as an excess contribution. This is a genuine escape hatch, but the original withdrawal has to have been a reasonable, good-faith mistake. You can’t use it to retroactively recharacterize a deliberate non-medical withdrawal.
How Long to Keep the Receipts
The general IRS audit window is three years from the date a return is filed. For HSAs there’s a twist. The rules let you reimburse yourself for a qualified medical expense at any time, as long as the expense was incurred after you established the account and you haven’t deducted or reimbursed it elsewhere.3Internal Revenue Service. Publication 969 – Health Savings Accounts and Other Tax-Favored Health Plans So you could pay a dental bill out of pocket in 2026 and take the tax-free reimbursement from your HSA in 2036.
The three-year audit clock runs from the return where the distribution appears, not from the year the expense was incurred. If the IRS questions that 2036 distribution and you claim it reimburses a 2026 bill, you need the 2026 invoice, the EOB, and proof that you never deducted or reimbursed the expense from another source. Losing the paperwork turns a tax-free withdrawal into taxable income with a 20% penalty. The practical answer is to keep HSA receipts indefinitely, not just three years.