California Code, Education Code - EDC § 56441.5

Appropriate instructional adult-to-child ratios for group services shall be dependent on the needs of the child.  However, because of the unique needs of individuals with exceptional needs between the ages of three and five years, inclusive, who require special education and related services, the number of children per instructional adult shall be less than ratios set forth in subdivision (c) of Section 8264.8 for young children in a regular preschool program.  Group services provided to individuals with exceptional needs between the ages of three and five years, inclusive, identified as severely disabled pursuant to Section 56030.5 shall not exceed an instructional adult-to-child ratio of one to five.