D.C. Mun. Regs. tit. 29, r. 29-552
A patient who is transported by ambulance into the District of Columbia shall only be transported by an EMS ambulance and crew that is certified by the state agency with jurisdiction at the point of origin.
The same transporting ambulance agency may perform the return transport of the same patient to the point of origin; provided, that the return transport shall be performed by a crew and ambulance that is appropriate for the condition of the patient.
If the requirements of § 552.2 cannot be met, the transport shall be considered a new transport, with its point of origin in the District of Columbia.
Transportation of a patient by an EMS ambulance or crew that is not certified in the jurisdiction of origin shall be reported to the state agency with jurisdiction over EMS services at the point of origin.
Long-term and assisted living facilities shall utilize private, commercial, non-emergency ambulance services for inter-facility transports instead of the District 9-1-1 emergency ambulance service whenever possible and consistent with the health and safety of the patient.
D.C. Mun. Regs. tit. 29, r. 29-552