D.C. Code § 47-4432

If a joint income tax return is filed, the Mayor shall separate the amount due to the spouse who owes delinquent taxes from the spouse who does not owe delinquent taxes based upon the proportion of gross income of each spouse. In applying the tax refund against delinquent taxes owed by a spouse, the tax refund of the spouse who does not owe delinquent taxes shall not be credited against the liability of the spouse who owes delinquent taxes. If a separate income tax return on a combined individual form prescribed by the Mayor is filed, the tax refund of the spouse who does not owe delinquent taxes shall not be credited against the liability of the spouse who owes delinquent taxes. If a real property tax refund is due to more than one owner of real property, the Mayor shall separate the amount of tax refund of the owners who are liable for delinquent taxes from the owners who are not liable for delinquent taxes determined on the basis of each owner’s ownership percentage in the real property. For the purposes of this section, the term “spouse” shall include a domestic partner who files under § 47-1805.01(d)[(d) repealed].