California Code, Education Code - EDC § 44065

(a) Except as provided in subdivision (d), any person employed on or after July 1, 1963, by a school district, including a district having the merit system as outlined in Article 6 (commencing with Section 45240) of Chapter 5 of this part, or by a county superintendent of schools, in a position in which 50 percent or more of his or her duties performed during the school year, whether performed in a particular school or district or countywide, consist of rendering service in directing, coordinating, supervising or administering any portion or all of the types of functions listed below in this section shall hold a valid teaching or service credential as appropriate, whichever is designated in regulations adopted by the Commission on Teacher Credentialing, authorizing the particular service.

The types of functions are:

(b) Any person who was employed by a district or by a county superintendent of schools before July 1, 1963, to perform any of the services designated by the Commission on Teacher Credentialing to require a supervision or administration credential, may continue to perform such services without possessing the credential otherwise required as long as he remains continuously employed to perform the same services in that county superintendent's office or in that district in which he was employed on that date, or is continuously employed to perform the same services in a district which results from a reorganization involving the same district.

(c) Notwithstanding any other provision of law, the governing board of any school district maintaining kindergarten or any of grades 1 to 12, inclusive, or providing adult education classes, may employ for purposes of instructing apprentices duly registered with the Division of Apprenticeship Standards, persons holding any of the following valid credentials:

(d) Notwithstanding subdivision (a), a school district or county superintendent of schools may hire persons who do not hold valid teaching or service credentials to perform the examination, selection or assignment of teachers, principals, or certificated personnel involved in the instructional program.