District of Columbia Code Division VII. Property. § 42-3131.03. Notice requiring correction of unlawful conditions; service.

(1) If delivered to the person to be notified, if sent by electronic mail to the last-known electronic mail address of the person to be notified, or if left, at the usual residence or place of business of the person to be notified, with a person of suitable age and discretion then resident therein;

(2) If no such residence or place of business can be found in said District by reasonable search, if left with any person of suitable age and discretion employed therein at the office of any agent of the person to be notified, which agent has any authority or duty with reference to the land or tenement to which said notice relates;

(3) If no such office can be found in the District by reasonable search, if forwarded by first-class mail to the last-known address of the person to be notified, or the person's agent, as determined by the tax records, business license records, or business entity registration records, and not returned by the post office authorities;

(4) If no address be known or can by reasonable diligence be ascertained, or if any notice forwarded as authorized by paragraph (3) of this section shall be returned by the post office authorities, if posted in a conspicuous place in or about the property affected by the notice; or

(5) If by reason of an outstanding, unrecorded transfer of title the name of the owner in fact cannot be ascertained beyond a reasonable doubt, if served on the owner of record in the manner hereinbefore in this section provided. Any notice required by law or by any regulation aforesaid to be served on a corporation shall for the purposes of this subchapter be deemed to have been served on any such corporation if served on the president, secretary, treasurer, general manager, or any principal officer of such corporation in the manner hereinbefore provided for the service of notices on natural persons holding property in their own right; and, if required to be served on any foreign corporation, if served on any agent of such corporation personally, or if left with any person of suitable age and discretion residing at the usual residence or employed at the place of business of such agent in the District of Columbia. Every notice aforesaid shall be in writing or printing, or partly in writing and partly in printing; shall be addressed by name to the person to be notified; shall describe with certainty the character and location of the unlawful condition to be corrected; and shall allow a reasonable time to be specified in said notice, within which the person notified may correct such unlawful condition or show cause why he should not be required to do so.