Cal. Welfare and Institutions Code § 16563

(a) If there is a child eligible for Tier 2 of the Care and Supervision component of the Tiered Rate Structure, as described in subdivision (h) of Section 11461, living in a resource family home, no more than a total of three children in foster care may be placed in that resource family home, including the child receiving the Tier 2 rate. (b) If there is a child eligible for Tier 3 or Tier 3+ of the Care and Supervision component of the Tiered Rate Structure, as described in subdivision (h) of Section 11461, living in a resource family home, no more than a total of two children in foster care may be placed in that resource family home, including the child eligible for Tier 3 or Tier 3+ . (c) A county placing agency may approve placements for additional children in foster care that would result in the placement of more than three children in foster care in a home where a child eligible for Tier 2 is placed or more than two eligible children in a home where a child eligible for Tier 3 or Tier 3+ is placed in compelling circumstances, including in order to accommodate a preexisting relationship, to place a sibling group together, or to accommodate the extraordinary needs of a specific child that the resource family has a unique ability to meet. A shortage of approved resource family homes shall not be a compelling circumstance absent other factors. (d) Approval for additional children in foster care to be placed in the home shall be determined to be in the best interest of all children in the home and shall come from the director of the county child welfare department or the chief probation officer of the county probation department, or their respective designees, of all of the county placing agencies with children placed or proposed to be placed in the home.