D.C. Code § 1-204.81

(a) Any act of the Council authorizing the issuance of general obligation bonds under § 1-204.61(a) shall provide for the annual levy of a special tax or charge, if the Council determines that such tax or charge is necessary. Such tax or charge shall be levied, without limitation as to rate or amount, in amounts which together with other District revenues available and applicable will be sufficient to pay the principal of and interest on such general obligation bonds as they become due and payable. Such tax or charge shall be levied and collected at the same time and in the same manner as other District taxes are levied and collected, and when collected shall be set aside in a separate debt service fund and irrevocably dedicated to the payment of such principal and interest.
(b) The Comptroller General of the United States shall make annual audits of the amounts set aside and deposited in each debt service fund pursuant to subsection (a) of this section.