Per the IRS Topic No. 203 Reduced Refund webpage:
The Department of Treasury's Bureau of the Fiscal Service (BFS) issues IRS tax refunds and Congress authorizes BFS to conduct the Treasury Offset Program (TOP). Through the TOP program, BFS may reduce your refund (overpayment) and offset it to pay:
You can contact the agency with which you have a debt to determine if your debt was submitted for a tax refund offset. You may call BFS's TOP call center at the number below for an agency address and phone number. If your debt meets submission criteria for offset, BFS will reduce your refund as needed to pay off the debt you owe to the agency. Any portion of your remaining refund after offset is issued in a check or direct deposited as originally requested on the return.
BFS will send you a notice if an offset occurs. The notice will reflect the original refund amount, your offset amount, the agency receiving the payment, and the address and telephone number of the agency. BFS will notify the IRS of the amount taken from your refund once your refund date has passed. You should contact the agency shown on the notice if you believe you don't owe the debt or if you're disputing the amount taken from your refund. Contact the IRS only if your original refund amount shown on the BFS offset notice differs from the refund amount shown on your tax return. If you don't receive a notice, contact the BFS's TOP call center at 800-304-3107 (or TTY/TDD 866-297-0517), Monday through Friday 7:30 a.m. to 5 p.m. CST.
Injured Spouse Claim
If you filed a joint return and you're not responsible for your spouse's debt, you're entitled to request your portion of the refund back from the IRS. You may file a claim for this amount by filing Form 8379, Injured Spouse Allocation.
You may file Form 8379 in any of the following ways:
When filing a Form 8379 with your joint return by mail or with an amended return, write "Injured Spouse" in the top left corner of the first page of the joint return.
The IRS can process your Form 8379 before an offset occurs. If you file Form 8379 with your original return, it may take 11 weeks to process an electronically-filed return or 14 weeks if you filed a paper return. If you file the Form 8379 by itself after a joint return has been processed, then processing will take about 8 weeks. To avoid delays, be sure to follow the Instructions for Form 8379.
When filing Form 8379 by itself, you must show both spouses' social security numbers in the same order as they appeared on your joint income tax return. You, the injured spouse, must sign the form. Follow the instructions on Form 8379 carefully and be sure to attach the required Forms W-2 and W-2G for both spouses and any Forms 1099 showing federal income tax withholding to avoid delays. Don't attach the previously filed joint tax return. Send Form 8379 to the Service Center where you filed your original return and allow at least 8 weeks for the IRS to process your request. The IRS will compute the injured spouse's share of the joint refund. If you lived in a community property state during the tax year, the IRS will divide the joint refund based upon state community property law. Not all debts are subject to a tax refund offset. To determine whether an offset will occur on a debt owed (other than federal tax), contact BFS's TOP call center at 800-304-3107 (866-297-0517 for TTY/TDD help).
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the webpage or document at the time it is accessed.