D.C. Code § 9-401.03
It shall be the duty of the Mayor of the District of Columbia to see that all water and gas mains, service pipes, and sewer connections are laid upon any street or avenue proposed to be paved or otherwise improved before any such pavement or other permanent works are put down; and the Washington Gas Light Company, under the direction of said Mayor, shall at its own expense take up, lay, and replace all gas mains on any street or avenue to be paved, at such time and place as said Mayor shall direct, except as provided in §§æ6-301.04(c) [repealed], 6-301.06(h) [repealed], and 9-107.02.
D.C. Code § 9-401.03
Sewer, water, and gas mains, excavation fees, see § 2-136 . Water and sewer systems, flood hazard prevention, see § 6-503 . Water mains and service sewers, see §§ 34-2401.01 and 34-2405.01 . .