California Code, Business and Professions Code - BPC § 4996.23.3

(a) An associate clinical social worker or an applicant for licensure shall only perform mental health and related services at the places where their employer permits business to be conducted.

(b) An associate who is employed by, or volunteering in, a private practice or a professional corporation shall be supervised by an individual who is both of the following:

(c) Supervisors of supervisees in a nonexempt setting shall not serve as individual or triadic supervisors for more than six supervisees at any time. Supervisees may be registered as associate marriage and family therapists, associate professional clinical counselors, associate clinical social workers, or any combination of those registrations.

(d) A written oversight agreement, as specified by the board by regulation, shall be executed between the supervisor and employer when the supervisor is not employed by the supervisee's employer or is a volunteer. The supervisor shall evaluate the site or sites where the supervisee will be gaining experience to determine that the site or sites comply with the requirements of this chapter.