Cal. Welf. & Inst. Code § 11450.16

(a) For purposes of determining eligibility under this chapter, and for computing the amount of aid payment under Section 11450, families shall be grouped into assistance units.
(b) Every assistance unit shall include at least one of the following persons:
1. (1) One of each of the following:
  1. (A) An eligible child.
  2. (B) The caretaker relative of an otherwise eligible child who is not receiving aid under Section 11250 because that child is receiving benefits under Title XVI of the Social Security Act (Subchapter 16 (commencing with Section 1381) of Chapter 7 of Title 42 of the United States Code), or Kin-GAP payments under Section 11364 or 11387, or foster care payments under Section 11461.
2. (2) A pregnant woman who is eligible for payments under subdivision (c) of Section 11450.
(c) Every assistance unit shall, in addition to the requirements of subdivision (b), include the eligible parents of the eligible child and the eligible siblings, including half-siblings, of the eligible child when those persons reside in the same home as the eligible child. This subdivision shall not apply to any convicted offender who is permitted to reside at the home of the eligible child as part of a court-imposed sentence and who is considered an absent parent under Section 11250.
(d) An assistance unit may, at the option of the family comprising the assistance unit, also include the nonparent caretaker relative of the eligible child, the spouse of the parent of the eligible child, otherwise eligible nonsibling children in the care of the caretaker relative of the eligible child, and the alternatively sentenced offender parent exempted under subdivision (c).
(e) If two or more assistance units reside in the same home, they shall be combined into one assistance unit when any of the following circumstances occurs:
1. (1) There is a common caretaker relative for the eligible children.
2. (2) One caretaker relative marries another caretaker relative.
3. (3) Two caretaker relatives are the parents of an eligible child.
(f) For purposes of this section, “caretaker relative” means the parent or other relative, as defined by regulations adopted by the department, who exercises responsibility and control of a child.