Welf. & Inst. Code, § 5151

(a) If the facility designated by the county for evaluation and treatment admits the person, it may detain the person for evaluation and treatment for a period not to exceed 72 hours from the time that the person was first detained pursuant to Section 5150. Saturdays, Sundays, and holidays may be excluded from the period if the State Department of Health Care Services certifies for each facility that evaluation and treatment services cannot reasonably be made available on those days. The certification by the department is subject to renewal every two years. The department shall adopt regulations defining criteria for determining whether a facility can reasonably be expected to make evaluation and treatment services available on Saturdays, Sundays, and holidays.

(b) Prior to admitting a person to the facility for treatment and evaluation pursuant to Section 5150, the professional person in charge of the facility or a designee shall assess the individual to determine the appropriateness of the involuntary detention. This assessment shall be made face-to-face either in person or by synchronous interaction through a mode of telehealth that utilizes both audio and visual components.