D.C. Code § 2-702: Permitted categories of official mail.

Except as otherwise provided in this chapter, a government employee may not mail, as official mail, any matter, article, material, or document for any reasons other than the following:

(1)

A request for the matter, article, material, or document has been previously received by the agency;

(2)

The mailing of the document is required by law;

(3)

The material or matter requests information pertinent to the conduct of the official business of the agency;

(4)

The material contains information relating to the activities of the agency or to the availability of agency publications or other documents;

(5)

The enclosures are forms, blanks, cards, or other documents necessary or beneficial to the administration of the agency;

(6)

The materials are copies of federal, state or local laws, rules, regulations, orders, instructions, or interpretations thereto; or

(7)

The materials are being mailed to federal, state, or other public authorities.