D.C. Mun. Regs. tit. 4, r. 4-1601
This chapter shall apply to all employers that employ twenty (20) or more persons in the District of Columbia on or after April 1, 1991; provided that this chapter shall not apply to the United States government.
A private employer shall be covered if it maintains twenty (20) or more employees on the payroll during twenty (20) or more calendar workweeks (whether consecutive or not) in either the current or the preceding calendar year.
Once a private employer meets the threshold of twenty (20) employees during twenty (20) workweeks as specified in § 1601.2, the employer shall remain covered until it no longer employs twenty (20) employees for twenty (20) workweeks (whether consecutive or not) in the current or preceding year.
For example, if an employer employed twenty (20) employees during twenty (20) workweeks in the calendar year as of September 1, 2008, then subsequently dropped below twenty (20) employees before the end of calendar year 2008 and continued to employ fewer than twenty (20) employees during that year, the employer would continue to be covered throughout calendar year 2009 because it met the coverage criteria for twenty (20) workweeks of the preceding calendar year 2008.
If the employer employs at least twenty (20) employees in the District, its eligible employees shall include those employees who work within the District. The definition of employee, and the standard to determine whether an employee is employed in the District, is set forth in section 1603.6.
The District of Columbia government shall be considered as a single employer under the DCFMLA, and the DCFMLA is applicable to every District government agency, office, and other subdivision, without regard to its individual size.
D.C. Mun. Regs. tit. 4, r. 4-1601