D.C. Mun. Regs. tit. 3, § 509
PROCESSING: BY MAIL
509.1 Prior to the thirtieth (30th) day preceding an election, a qualified elector, or a person who is qualified to register (pursuant to D.C. Official Code § 1-1001.07 (a-2)), may register to vote, or change his or her name, address, or party affiliation status by mailing a complete voter registration application to the Board.509.2 If the registration by-mail deadline falls on a Saturday, Sunday, or holiday, the deadline shall be extended to the next business day.509.3 The Board shall process mailed voter registration applications and registration update notifications received postmarked by not later than the thirtieth (30th) day preceding any election.509.4 Mailed voter registration applications and update notifications considered received during the thirty (30) days that immediately precede and include the date of the election shall be held and processed after the election.509.5 The Board shall process timely completed non-postmarked voter registration applications and registration update notifications mailed and received not later than the twenty-third (23rd) day preceding any election.509.6 A voter registration application, or a notice of change of name, address, or party affiliation status, which is delivered by mail and postmarked by the United States Postal Service is considered received by the Board on the date of the postmark.509.7 A voter registration application, or a notice of change of name, address, or party affiliation status, delivered without a postmark shall be considered to be received by the Board upon acknowledgement of receipt by an agency date-stamp; provided that if a voter registration application, or a notice of change of name, address, or party affiliation status is delivered by common carrier, it is considered received by the Board on the parcel's shipping date.509.8 The Board will take steps to reasonably investigate the timely completion of non-postmarked voter registration applications, or notices of change of name, address, or party, by checking tracking numbers or any other information available.509.9 Individuals who have not previously voted in a federal election in the District and who register to vote by mail shall present, either at the time of registration, at the polling place, or when voting by mail, either a copy of a current and valid government photo identification, a copy of a current utility bill, bank statement, government check, paycheck, or other government document that shows the name and address of the
voter.
509.10 Subsection 509.9 shall not apply to:
(a) Individuals whose registration application includes either a driver's license number or at least the last four (4) digits of his or her social security number and with respect to whom the Board has been able to match the provided information with an existing identification record bearing the same number, name and date of birth as provided in such registration application; and
(b) Individuals entitled to vote otherwise than in person under Federal law.
SOURCE: Final Rulemaking published at 43 D.C. Reg. 1078, 1084-86 (March 1, 1996); as amended by Final Rulemaking published at 56 D.C. Reg. 4738, 4740 (June 19, 2009); and as amended by Final Rulemaking published at 57 D.C. Reg. 3267, 3277 (April 16, 2010); as amended by Notice of Emergency and Proposed Rulemaking published at 7 DCR 7690 (August 20, 2010)[EXPIRED]; as amended by Notice of Final Rulemaking published at 57 DCR 11111, 11115(November 26, 2010).