If you’re wondering why you’re getting a letter from the Ohio Department of Taxation, it almost always comes down to one of a handful of issues: a return the department expected but didn’t receive, an unpaid balance, income on your state return that doesn’t match what the IRS has on file, a deduction or credit the department is adjusting, an identity check before a refund goes out, a refund offset to pay another debt, a residency question, or an audit. The first thing to look for on the notice is the response deadline. Once it passes, an assessment can become final and collection can start.
You Didn’t File, or Filed Late
Ohio individual income tax returns (IT 1040) are due April 15. Ohio doesn’t have its own extension form but honors the federal IRS extension, which moves the filing deadline to October 15. Any tax you owe is still due April 15 regardless of an extension.1Ohio Department of Taxation. Individual Filing Season Tips
If the department expected a return and didn’t get one, you’ll get a notice even if you owe nothing. A late-filing penalty of $50 per month can apply, up to a maximum of $500, whether or not there’s a balance due.2Ohio Department of Taxation. Individual Income Tax Failure to File Notice Filing a few weeks late costs far less than waiting several months.
You Owe a Balance
If the letter shows tax owed plus penalties and interest, that’s the most common reason ODT writes. Ohio sets an interest rate on unpaid taxes each year. For 2026, the rate is 7%.3Ohio Department of Taxation. Annual Certified Interest Rates The late-payment penalty runs at double the interest rate, so for 2026 that’s 14% on top of what you owe.2Ohio Department of Taxation. Individual Income Tax Failure to File Notice Those charges keep accumulating, which is why a small debt can grow quickly if you let it sit.
One thing to know up front: ODT itself does not set up payment plans. Once a liability goes unpaid long enough, the department certifies the debt to the Ohio Attorney General’s office, which is where installment agreements are actually negotiated. The AG typically requires the balance paid in full within 12 months and can add collection fees on top of the existing penalties and interest. Responding before the account is certified gives you the best chance of keeping those extra costs down.
Your Income Doesn’t Match Federal Records
ODT cross-checks your state return against federal filings and third-party income reports like W-2s and 1099s.4Internal Revenue Service. State Information Sharing If freelance income appears on your federal return but was left off your Ohio return, the mismatch will show up.
The notice will identify the specific income source and give you a chance to either agree with the adjustment or send documentation showing the original return was right. Pay stubs, 1099 forms, or other records that back up the numbers you filed are usually what the department wants. Responding beats ignoring the letter, because ODT generally gives you time to resolve the discrepancy before treating the higher amount as final.
A Deduction or Credit Was Adjusted
Some deductions and credits get reviewed for compliance. Medical and health care expenses, for example, are deductible only to the extent they exceed 7.5% of your federal adjusted gross income.5Ohio Department of Taxation. Income – Medical and Health Care Expenses Other credits, like the Scholarship Donation Credit, require specific documentation.6Ohio Department of Taxation. Ohio Tax Credits and Their Required Documentation
When the department finds that something you claimed doesn’t meet the requirements, it adjusts the return and sends a letter showing the revised liability and which line changed. Hold onto receipts, donation acknowledgment letters, and insurance statements for at least four years after filing, which is Ohio’s standard reassessment window.
The Department Needs to Verify Your Identity
Not every letter means something is wrong. ODT sometimes sends identity verification letters before processing a return or releasing a refund, as a safeguard against tax fraud and identity theft.7Ohio Department of Taxation. Identity Verification and Identity Theft The letter will walk you through the steps, which usually involve uploading documents online or mailing copies.
You’ll be asked for three things: proof of your Social Security number or ITIN (such as your Social Security card), proof of identity (driver’s license, military ID, or passport), and proof of return (your federal return pages 1 and 2).8Ohio Department of Taxation. ID Verification Letter Review can take up to 60 days. If someone filed using your information, the verification letter may be how you first learn about it.
Your Refund Was Offset
A letter saying your refund was reduced or eliminated means Ohio applied part or all of it to another debt. Offsets cover unpaid state taxes, federal taxes, child or spousal support owed through Ohio Job and Family Services, workers’ compensation premiums owed to the Ohio Bureau of Workers’ Compensation, and other debts certified to the Attorney General’s office. The notice names the agency that received the money and the amount applied.9Ohio Department of Taxation. Was Your Refund Offset
Once applied, ODT cannot reverse an offset. If you think the underlying debt is wrong, contact the agency listed on the letter directly. If you filed jointly and only your spouse owes the debt, the offset notice includes a Non-Liable Spouse worksheet. Return it by the deadline on the letter or you lose the ability to reclaim your share.9Ohio Department of Taxation. Was Your Refund Offset
Ohio Has a Question About Your Residency
Residents owe Ohio tax on all income. Nonresidents owe Ohio tax only on income sourced inside the state. Residents who pay income tax to another state can claim a credit for it, except for wages taxed by Kentucky, Michigan, Indiana, Pennsylvania, or West Virginia, which have reciprocal agreements with Ohio.10Ohio Department of Taxation. What Does Ohio Residency Mean for Taxes
If the address or residency status on your return conflicts with other information the department has, a letter will ask for clarification. A lease, mortgage statement, voter registration, or similar record usually resolves it. Getting residency wrong can mean paying tax you don’t owe or missing tax you do.
Your Return Was Selected for Audit
An audit letter means the department is reviewing your return more closely. Ohio’s tax commissioner has statutory authority to inspect books, accounts, records, and other documents of anyone subject to Ohio tax laws.11Ohio Legislative Service Commission. Ohio Revised Code 5703.19 The notice specifies the tax years, the type of audit, and the documents to produce.
Cooperating matters. If you get at least ten days’ written notice requesting records and refuse to comply, the penalty is $500 per day of noncompliance.11Ohio Legislative Service Commission. Ohio Revised Code 5703.19 Not every audit implies wrongdoing. Some are routine. But if the department finds a fraudulent attempt to evade tax, the penalty is the greater of $1,000 or 100% of the tax that should have been reported.12Ohio Legislative Service Commission. Ohio Revised Code Chapter 5747 – Section 5747.15
Ohio generally has four years from the filing deadline or the date you filed (whichever is later) to assess additional tax. There’s no time limit for a fraudulent return or an unfiled one. You and the tax commissioner can also agree in writing to extend the four-year window.13Ohio Legislative Service Commission. Ohio Revised Code 5747.13
Earlier Letters Went Unanswered
If prior notices got no response, the department escalates. An enforcement notice means ODT is preparing to collect using legal tools. Unresolved balances are certified to the Ohio Attorney General’s office, which can pursue wage garnishment, bank levies, and property liens. These notices usually include a timeline and the steps still available to stop enforcement: paying in full, negotiating an installment agreement through the AG, or filing a petition for reassessment if you dispute the amount. By this stage, penalties and interest have been accumulating for months, so responding now is still better than doing nothing.
What to Do After You Read the Letter
Watch the 60-Day Petition Deadline
If the letter is an assessment notice, you have 60 days from the date it was served to file a petition for reassessment with the tax commissioner. The petition must be in writing, identify the specific items you’re contesting, and explain why you disagree. You can also request a hearing. Miss the 60 days and the assessment becomes final, with tax, penalties, and interest immediately due and payable.14Ohio Department of Taxation. Petition for Reassessment
You can submit the petition by mail, fax, or email. If you mail it, use certified mail with a return receipt so you have proof it was sent before the deadline.
If You Want a Professional to Handle It
If you want a CPA, tax attorney, or enrolled agent to deal with ODT for you, file Ohio Form TBOR 1, Declaration of Tax Representative.15Ohio Department of Taxation. Declaration of Tax Representative Without that form on file, the department won’t discuss your account with anyone else, even someone you’ve hired. For audit notices and larger disputed assessments, getting representation set up early is worth it.
Keep Your Records
Because Ohio’s standard assessment window is four years from your filing deadline or the date you filed, whichever is later, keep tax records for at least that long.13Ohio Legislative Service Commission. Ohio Revised Code 5747.13 If you claimed large deductions, reported complex income, or took positions you’re not fully sure about, hold them longer. The window stretches further for substantial underreporting and has no limit at all for fraud or an unfiled return.