California Code, Education Code - EDC § 44929.22

At the discretion of the governing board of a district with 60,000 average daily attendance or more every employee of the district who, after having been employed by the district for two consecutive school years in a position or positions requiring certification qualifications, is reelected for the next succeeding school year to a position requiring certification qualifications may, at the commencement of the succeeding school year, be classified as and become a permanent employee of the district. If the board is the governing board of more than one district, it may exercise the discretionary power given it by this section in each district under its jurisdiction, whether or not each of the districts has 60,000 average daily attendance.

This section shall apply only to probationary employees whose probationary period commenced prior to the 1983-84 fiscal year.