D.C. Code § 21-561
§ 21-561. Mail privileges; censored mail; return to sender; visiting hours.
(a) A person hospitalized in a public or private hospital pursuant to this chapter , or committed under §§ 21-545 , 21-545.01 , or 21-548 , may exercise the right to communicate with others as set forth in § 7-1231.01 et seq .
(b) Repealed.
(c) This section does not prohibit the administrator of a hospital from making reasonable rules regarding visitation hours.