D.C. Mun. Regs. tit. 3, r. 3-514
For registration applications and update notifications received at least twenty-one (21) days prior to an election, the Executive Director or his or her designee shall mail a non-forwardable voter registration notification to the applicant advising him or her of the acceptance or rejection of the registration application within nineteen (19) calendar days after the receipt of the registration application or update notification. If the application is rejected, the notification shall include the reason or reasons for the rejection and shall inform the voter of his or her right to either submit additional information as requested by the Board, or appeal the rejection pursuant to D.C. Official Code § 1-1001.07(f) (2016 Repl.).
In the event that the notification advising the applicant of acceptance of his or her voter registration is returned to the Board as undeliverable, the Executive Director or his or her designee shall mail the notice provided in D.C. Official Code § 1-1001.07(j)(1)(B) (2016 Repl.).
For registration applications received within the twenty (20)-day period immediately preceding an election, the Board shall mail each registered voter who filed a voter registration application or update notification a non-forwardable address confirmation notice to the applicant as soon as practicable after the election. If the United States Postal Service returns the address confirmation notification as "undeliverable," the Board shall notify the Attorney General of the District of Columbia.
D.C. Mun. Regs. tit. 3, r. 3-514