D.C. Mun. Regs. tit. 11, § 2806
2806.1 Except as prohibited by § 2805, accessory uses (including parking, but not at-grade accessory surface parking lots) buildings, or structures customarily incidental and subordinate to the principal uses permitted in § 2802 shall be permitted in the HE District as a matter of right subject to the limitations in Chapter 25 of this Title.