District of Columbia Code Division V. Local Business Affairs § 32-531.03. Notification.

Paid leave shall be provided upon the written request of an employee upon notice as provided in this section. The request shall include a reason for the absence involved and the expected duration of the paid leave. If the paid leave is foreseeable, the request shall be provided at least 10 days, or as early as possible, in advance of the paid leave. If the paid leave is unforeseeable, an oral request for paid leave shall be provided prior to the start of the work shift for which the paid leave is requested. In the case of an emergency, the employer shall be notified prior to the start of the next work shift or within 24 hours of the onset of the emergency, whichever occurs sooner.