California Code, Family Code - FAM § 4560

(a) Except as provided in subdivision (b) or in Article 3 (commencing with Section 4565), every order or judgment to pay child support may also require the payment by the child support obligor of up to one year's child support or such lesser amount as is equal to the child support amount due to be paid by the child support obligor between the time of the date of the order and the date when the support obligation will be terminated by operation of law. This amount shall be known as the “child support security deposit.”

(b) Unless expressly waived by the child support obligee, the court may order the establishment of a child support trust account pursuant to this chapter in every proceeding in which a child support obligation is imposed by order of the court. Among other reasons, the court may decline to establish a child support trust account upon its finding that an adequately funded child support trust account already exists pursuant to this chapter for the benefit of the child or children involved in the proceeding or that the child support obligor has provided adequate alternative security which is equivalent to the child support security deposit otherwise required by this chapter.