Cal. Penal Code § 832.4

(a) Any undersheriff or deputy sheriff of a county, any police officer of a city, and any police officer of a district authorized by statute to maintain a police department, who is first employed after January 1, 1974, and is responsible for the prevention and detection of crime and the general enforcement of the criminal laws of this state, shall obtain the basic certificate issued by the Commission on Peace Officer Standards and Training within 18 months of his or her employment in order to continue to exercise the powers of a peace officer after the expiration of the 18-month period.
(b) Every peace officer listed in subdivision (a) of Section 830.1, except a sheriff, or elected marshal, or a deputy sheriff described in subdivision (c) of Section 830.1, who is employed after January 1, 1988, shall obtain the basic certificate issued by the Commission on Peace Officer Standards and Training upon completion of probation, but in no case later than 24 months after his or her employment, in order to continue to exercise the powers of a peace officer after the expiration of the 24-month period.
Deputy sheriffs described in subdivision (c) of Section 830.1 shall obtain the basic certificate issued by the Commission on Peace Officer Standards and Training within 24 months after being reassigned from custodial duties to general law enforcement duties.
In those cases where the probationary period established by the employing agency is 24 months, the peace officers described in this subdivision may continue to exercise the powers of a peace officer for an additional three-month period to allow for the processing of the certification application.
(c) Each police chief, or any other person in charge of a local law enforcement agency, appointed on or after January 1, 1999, as a condition of continued employment, shall obtain the basic certificate issued by the Commission on Peace Officer Standards and Training within two years of appointment.