Cal. PROB § 5011

Notwithstanding any other provision of this part, the rights of the parties in a nonprobate transfer of community property on death are subject to all of the following: (a) The terms of the instrument under which the nonprobate transfer is made. (b) A contrary state statute specifically applicable to the instrument under which the nonprobate transfer is made. (c) A written expression of intent of a party in the provision for transfer of the property or in a written consent to the provision.