District of Columbia Code Division I. Government of District. § 8-1841.02. License; immunizations.

(a) All commercial guard dogs shall have a valid commercial guard dog license issued pursuant to District law. Upon issuance of a license, the Mayor shall issue a fluorescent guard dog identification tag, or such other tag as the Mayor determines appropriate, to be affixed to the collar or harness of the commercial guard dog to indicate the dog is a commercial guard dog.

(b) All commercial guard dogs shall be immunized against rabies and distemper pursuant to District law, and a current and valid certificate of these immunizations shall be retained on file by the owner of the commercial guard dog.