Charles Trautman, EA · Since 1969
What happens when you don’t file, what it costs, and how to get caught up.
Missing a year or two of tax returns is more common than people think: a job change, a divorce, an illness, a business that went sideways, and suddenly it’s been three years. The IRS gets most of the attention, but Colorado has its own rules, its own deadlines and its own collectors. Here is how the Colorado side works, and why getting caught up is usually less painful than people fear. Often the state owes you money.
Current as of October 2026. Part of our Colorado income tax series. For the federal side, see unfiled tax returns.
Many people who stop filing had Colorado tax withheld from their paychecks, or qualified for refundable credits. That money is waiting, but not forever.
Colorado gives you four years from a return’s original due date to file and claim a refund. That’s a year longer than the IRS allows. After four years, the refund is gone for good, even though the state can still collect from you for the same year.
Colorado’s child tax credit, earned income credit and, in the years it was available, the family affordability credit pay out even if you owe nothing. A family with young children can be owed thousands of dollars for a year they never filed.
In years with a state surplus, the TABOR sales tax refund must be claimed on a return filed by October 15 following the tax year. File later and you may still get your other refunds, but not that one. More on TABOR refunds.
The 2022 Colorado return was due April 18, 2023, so the four-year window to claim a 2022 refund closes in April 2027. The federal window for 2022 has already closed.
Colorado receives your W-2s and 1099s and shares information with the IRS. It knows when a return is missing.
| Step | What happens |
|---|---|
| 1. The state files for you | The Department of Revenue can prepare a return on your behalf from the information it has, and bill you for the tax. It counts as an assessment just as if you had filed. A return built that way usually leaves out deductions and credits you would have claimed. |
| 2. Notice of Deficiency | The bill. You have 30 days to dispute it. This is the cheapest time to act: paying or setting up payment within those 30 days keeps the lower interest rate. |
| 3. Final Determination | If you don’t pay or dispute the bill in time, it becomes final and the state demands payment. |
| 4. Notice of intent to lien | A last letter giving you 10 days to pay in full with certified funds. |
| 5. Lien and collection | A lien filed with the county attaches to everything you own and blocks a sale or refinance until the tax is paid. The state can also take wages, bank accounts, cars, boats and real estate, keep your state and federal refunds, or send the debt to a collection agency. |
Colorado normally has four years after you file to assess more tax. That clock never starts if you don’t file, so an unfiled year stays open indefinitely. Filing, even late, is what starts it.
The greater of $5 or 5% of the unpaid tax, plus another 0.5% for each month it stays unpaid, up to 12% in total.
Interest runs from the original due date until you pay. The rate is lower if you pay before the state sends a bill, or within 30 days after. For 2026 it’s 8% discounted, 11% regular.
| Step | Before a bill | After a bill |
|---|---|---|
| Tax owed | $3,000 | $3,000 |
| Penalty (maximum 12%) | $360 | $360 |
| Interest, April 2023 to October 2026 | $805 | $1,119 |
| Total | $4,165 | $4,479 |
Interest at the Department of Revenue’s published rates for 2023–2026, figured simply. Acting before the state sends a bill saves about $300 here, and the gap grows every year.
W-2s, 1099s and any letters from the IRS or Colorado. If records are missing, the IRS can provide wage and income transcripts for past years, and we can request them for you.
Colorado starts from your federal return, so the two are prepared as a set. If the state has already filed an estimated return for you, your own return usually replaces it, often with a lower bill.
Colorado offers payment plans through Revenue Online or by calling Collections. Penalties and interest keep running, and a missed payment or a missed future return cancels the plan.
File every year from here on, on time, even if you can’t pay. A plan only holds as long as new returns keep coming in.
The IRS generally wants the last six years filed. We usually start there for Colorado as well, then check whether the state has already estimated any earlier year. Years where you’re owed a refund within the four-year window go to the front of the line.
If I don’t file, Colorado won’t notice.
It will. Employers and banks report to the state, and Colorado and the IRS share information. The state can file a return for you, and it won’t be in your favor.
If I can’t pay, there’s no point in filing.
Filing still helps. It replaces any estimated return the state made, starts the four-year clock, and protects any refund or credit you’re owed. A payment plan is only available once the returns are in.
After seven years it goes away.
Not for an unfiled year. With no return, Colorado’s time limit to assess never starts. Your time to claim a refund, on the other hand, does run out after four years.
The state will take my house.
Usually it’s a lien first. A lien doesn’t take the house, but it attaches to it and blocks a sale or refinance until the tax is paid. That’s often when people find out, at the closing table.
We prepare past-due federal and Colorado returns together, year round, in Lone Tree, and handle the letters, payment plans and liens that come with them.
These pages are general information, current as of October 2026, and are not advice about your situation. Colorado law changes every session, and the Department of Revenue updates its publications through the year. Confirm anything that matters to you at tax.colorado.gov or call us.