Taxpayer Identity Verification

The Colorado Department of Revenue (CDOR) routinely takes precautionary measures to ensure taxpayer refunds are not diverted to identity thieves. The Department reviews all income tax refunds because it is operating in the public trust with revenue dollars collected and refunded. CDOR has several refund factors it reviews, including factors for refund fraud related to identity theft. The objective is to protect taxpayer information to ensure taxpayers receive the Colorado state income tax refund to which they are entitled. However, these measures may delay any expected refund.

Correspondence from CDOR

Part of the process of preventing fraud while protecting legitimate income tax refunds involves contacting taxpayers to ask them to verify their identities and other personal information related to income tax filing. The Colorado Department of Revenue sends this correspondence by U.S. Postal Service. The Colorado Department of Revenue will not call or send an email to you requesting this information.

Some letters from the Department direct taxpayers to mail or fax the requested information to the Colorado Department of Revenue. It is understandable that taxpayers will worry that these are not legitimate requests from the Department. However, only YOU should have this information. That is why the Department requests confirmation about a return that either you or someone else has filed under your name. Taxpayers should also pay attention to whether their tax professional or a spouse has indeed filed a return on their behalf. It is possible a legitimate return has been filed. Sometimes taxpayers are unaware the return has already been submitted by someone they have authorized to file the return.

If you receive a letter from us, please respond quickly to ensure that you get your refund to you as soon as possible. Refunds will be delayed until CDOR receives the requested information. If you do not respond, your return will not be processed. See a sample of CDOR official correspondence to verify that the letter you received is from the Department.


Possible Documents or Information the Department May Request in Support of a Colorado Tax Refund

  • Copy of Driver License or ID
  • Copy of a document containing your name and address. ​​
  • Copy of W-2(s) and/or 1099(s) claiming Colorado tax withholding. ​​
  • Refund Amount.​
  • ​​Validation Key. The Department has implemented a "Validation Key" process where information will be requested to be entered on Revenue Online to validate their Colorado refund. ​ Revenue Online is the fastest, safest and most secure means to upload requested documents.

Types of Correspondence

Validation Key Letter from the Colorado Department of Revenue

The Colorado Department of Revenue is taking additional precautions to verify information on the tax returns we process because of an increase in criminal activity surrounding illegal access to personal information. We need your help to confirm that the tax return was truly filed by you. Please complete the steps on the letter within 30 days from the date listed on the letter. If you do not complete the validation process within 30 days, your Colorado income tax return will NOT be processed and any claimed refund amount will NOT be issued.

If you have submitted your Colorado tax return:

  • Please visit Revenue Online and click on "Provide Validation Key" under Quick Links. Enter your last name and the validation key listed on the letter. Then click the “Yes” button to verify you (or your authorized representative, tax preparer, etc.,) submitted the return and enter your Refund Amount. 
  • If you require assistance completing the validation process, you may contact the taxpayer helpline at (303) 238-7378.

If you did not submit your Colorado tax return: 

  • Your personal identity and information may have been compromised and used to file a fraudulent Colorado tax return. The Colorado Department of Revenue tax accounting system has NOT been compromised. Our Revenue Online service has NOT been compromised. The fraud perpetrators are obtaining this information through other means, such as security breaches of businesses, health care, educational institutions, military, banking, credit or financial databases.
  • Please visit Revenue Online and click on "Provide Validation Key" under Quick Links. Enter your last name and the validation key listed on the letter. Report the return as fraudulent by answering “NO” to the “Did you (or your authorized representative, tax preparer, etc.,) submit this return?” question.

Paper Check instead of Direct Deposit

Colorado income tax refunds that were requested to be direct deposited may be converted to a paper check. Sending a paper check to the taxpayer’s mailing address is intended to prevent criminals from easily diverting fraudulent refund to their own prepaid, reloadable cards or debit cards. Receiving a paper check does not mean a taxpayer’s identity has been compromised. It is a safeguard measure implemented by the Department. If you receive a letter and paper income tax refund check from the Colorado Department of Revenue this year and you have not filed your tax return yet or you are not expecting a refund, you may call the fraud hotline number included in the letter. The Department appreciates taxpayers’ patience and understanding while it takes necessary steps to protect Colorado income tax refunds.

If you need to report a possible individual income tax refund fraud issue, please send us an online request through our Report Tax Refund Fraud online form or contact us at 303-205-8292.


You Received a Validation Key Letter, but Did Not Respond Within 30 Days

You can verify by email, fax or mail.  Please follow these instructions to verify if you filed your tax return. If you do not complete the validation process, your Colorado income tax return will NOT be processed and any claimed refund amount will NOT be issued. Provide your Colorado Account Number on any documents submitted, which can be found in the upper right corner of your letter.

If you submitted a Colorado tax return: 

We require additional documents to validate your identity and tax return.  Please submit a copy of one document from each category below:

Category 1: A document that has your full name and photograph. Examples are a Colorado Driver License or ID, Passport, Military ID or another government-issued ID.

Category 2: A document that has your full name and complete address used on your Colorado income tax return. Examples are a utility bill (electric, cable, phone, etc.), bank or credit card statement, payroll stub or insurance statement or a rental agreement.

AND

  • A copy of your Validation Key letter (The letter title is ACTION NEEDED.)
  • Also provide the amount of the refund claimed on your Colorado return.

If you did not submit a Colorado tax return: 

Please let the Department of Revenue know that you did NOT submit the return by responding to the letter using one of the contact options below. Provide your Colorado Account Number on any documents submitted, which can be found in the upper right corner of your letter.

Submit the required documents by email, fax or mail to:

  • Email the Discovery Section: DOR_Discovery@state.co.us 
  • Fax: 303-866-3018
  • Mail:
    Colorado Department of Revenue
    Discovery Section, Room 634
    PO Box 17087
    Denver, CO 80217-0087

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