D.C. Mun. Regs. tit. 5, r. 5-E606
In conjunction with the filing of a petition for recognition pursuant to the provisions of § 602 of this chapter, the petitioner shall simultaneously submit to the Board of Labor Relations evidence that at least thirty percent (30%) of the employees in the appropriate bargaining unit desire to have the petitioner represent them for the purposes of collective bargaining.
In conjunction with the filing of a petition for decertification pursuant to the provisions of § 603 of this chapter, the petitioner shall simultaneously submit to the Board of Labor Relations evidence that at least thirty percent (30%) of the employees in the unit, or in each unit, do not desire to be represented by the certified labor organization.
Evidence of proof of interest in the filing of a petition for recognition or a petition for decertification, as required by §§ 606.1 and 606.2, shall consist of authorization cards or petitions that have been dated and signed by each employee claimed as part of the show of interest.
Authorization cards or petitions shall be dated and signed within the six (6) month period immediately preceding the date of submission of the petition to the Superintendent. Cards that were dated and signed prior to the six (6) month period shall not be counted in determining whether a sufficient show of interest has been made.
The number of employees required to meet the thirty percent (30%) requirement for show of interest shall be determined from the payroll records of the payroll period immediately preceding the filing of the petition, unless the Board of Labor Relations determines that that period is unrepresentative of the total number of employees. When the Board of Labor Relations determines that the period immediately preceding the filing of the petition does not accurately represent the total number of employees, the Board of Labor Relations shall determine the appropriate payroll period.
The determination by the Board of Labor Relations as to the sufficiency or non- sufficiency of a show of interest with regard to any petition shall be deemed a ministerial act which shall be binding upon the Board and the petitioner and not subject to challenge by either party.
Failure to simultaneously file evidence of interest in the petition, as required by this section, shall automatically disqualify the petition, and the Superintendent shall dismiss the petition.
D.C. Mun. Regs. tit. 5, r. 5-E606