S.D. Codified Laws § 27A-15-3
Except as otherwise provided in this section, a minor, whether admitted by a parent or involuntarily committed, may not be placed with adult patients, if the inpatient psychiatric facility maintains a separate unit for minors.
A minor may be admitted or committed to a facility that does not maintain a separate unit for minors, only for acute treatment and evaluation and only for a period not to exceed seven working days. The facility shall provide separate sleeping quarters and separate day areas in which adult patients are not permitted.
A patient who does not meet the definition of a minor, as set forth in § 27A-15-1, but is less than nineteen years of age, may be placed in a separate unit with minors if the patient:
The facility shall provide a separate evaluation program for which specific guidelines must be approved by the Department of Health.
SDCL 27A-15-3