FAMILY CODE SECTION 3080-3089
3080. There is a presumption, affecting the burden of proof, that joint custody is in the best interest of a minor child, subject to Section 3011, where the parents have agreed to joint custody or so agree in open court at a hearing for the purpose of determining the custody of the minor child.
3081. On application of either parent, joint custody may be ordered in the discretion of the court in cases other than those described in Section 3080, subject to Section 3011. For the purpose of assisting the court in making a determination whether joint custody is appropriate under this section, the court may direct that an investigation be conducted pursuant to Chapter 6 (commencing with Section 3110).
3082. When a request for joint custody is granted or denied, the court, upon the request of any party, shall state in its decision the reasons for granting or denying the request. A statement that joint physical custody is, or is not, in the best interest of the child is not sufficient to satisfy the requirements of this section.
3083. In making an order of joint legal custody, the court shall specify the circumstances under which the consent of both parents is required to be obtained in order to exercise legal control of the child and the consequences of the failure to obtain mutual consent. In all other circumstances, either parent acting alone may exercise legal control of the child. An order of joint legal custody shall not be construed to permit an action that is inconsistent with the physical custody order unless the action is expressly authorized by the court.
3084. In making an order of joint physical custody, the court shall specify the rights of each parent to physical control of the child in sufficient detail to enable a parent deprived of that control to implement laws for relief of child snatching and kidnapping.
3085. In making an order for custody with respect to both parents, the court may grant joint legal custody without granting joint physical custody.
3086. In making an order of joint physical custody or joint legal custody, the court may specify one parent as the primary caretaker of the child and one home as the primary home of the child, for the purposes of determining eligibility for public assistance.
3087. An order for joint custody may be modified or terminated upon the petition of one or both parents or on the court's own motion if it is shown that the best interest of the child requires modification or termination of the order. If either parent opposes the modification or termination order, the court shall state in its decision the reasons for modification or termination of the joint custody order.
3088. An order for the custody of a minor child entered by a court in this state or any other state may, subject to the jurisdictional requirements in Sections 3403 and 3414, be modified at any time to an order for joint custody in accordance with this chapter.
3089. In counties having a conciliation court, the court or the parties may, at any time, pursuant to local rules of court, consult with the conciliation court for the purpose of assisting the parties to formulate a plan for implementation of the custody order or to resolve a controversy which has arisen in the implementation of a plan for custody.