D.C. Code § 1-306.42: Building permits associated with street or alley closings or zoning density increases.

An applicant who obtains a street or alley closing or a zoning density increase who is required to construct or rehabilitate affordable housing pursuant to this part shall not be issued a building permit for the applicant’s commercial development until the applicant certifies to the District either that a building permit has been issued for the required amount of affordable housing, or that the applicant has contributed sufficient funds to a housing provider to construct or rehabilitate the required amount of affordable housing.