District of Columbia Code Division VIII. General Laws. § 47-2853.121. Scope of practice for plumbers or gasfitters.

(a) For the purposes of this part, the term “plumber” means any person who designs, installs, repairs or removes plumbing fixtures intended to receive and discharge water, liquid, or water-carried wastes into the drainage system with which they are connected; or who introduces, maintains or extends a supply of water through a pipe or pipes, or any appurtenance thereof, in any building, lot premises, or establishment; or who connects or repairs any system of drainage whereby foul, waste, or surplus water, sewer gases, vapor or other fluid is discharged or proposed to be discharged through a pipe or pipes from any building, lot, premises or establishment into any public or house sewer, drain, pit, box filter bed or other receptacle or into any natural or artificial watercourse flowing through public or private property; or who ventilates any building, sewer or fixture or appurtenance connected therewith; or who excavates any public or private street, highway, road, court, alley or space for the purpose of connecting any building, lot, premises, or establishment with any service pipe, house sewer, public water main, private water main, public sewer, private sewer, subway, conduit, or other underground structure.

(b) For the purposes of this part, the term “gasfitter” means any person who designs, fabricates, installs, tests or operates any nonindustrial type of gas appliance and piping system from the outlet of the meter set assembly, or from the outlet of the service regulator when a meter is not provided, to the inlet connections of appliances, for fuel gases such as natural gas, manufactured gas, undiluted liquefied petroleum gas, liquefied petroleum gas-air mixtures or mixtures of any of these gases; or who introduces, maintains or extends a supply of a gas through a pipe or pipes, or any appurtenance thereof, in any building, lot premises, or establishment; or who ventilates any fixture or appurtenance connected therewith; or who excavates any public or private street, highway, road, court, alley or space for the purpose of connecting any building, lot, premises, or establishment with any service pipe.