If the credit allowed under § 47-1806.09a exceeds the total income tax liability of the eligible resident under § 47-1806.03 for the tax year in which the credit is allowed, the eligible resident may claim a refund in the amount of the excess.
D.C. Code § 47-1806.09e — under Tax on Residents and Nonresidents..
D.C. Code § 47-1806.09e
If the credit allowed under § 47-1806.09a exceeds the total income tax liability of the eligible resident under § 47-1806.03 for the tax year in which the credit is allowed, the eligible resident may claim a refund in the amount of the excess.