Joint Title Presumption of Marital Property
Family Code section 2581 creates a presumption that property which is acquired in joint names during the marriage, whether or not the title document uses the words "community property", is in fact presumed to be CP. It applies both to real property (i.e., the home) and personal property (i.e., vehicles). A writing is required to rebut the presumption - alleged oral transmutations or changes to the joint verses separate character of property generally cannot be used to show something different from record title. Oral agreements just aren't deemed trustworthy or as products of mature reflection. Keep in mind, however, that Family Code section 2640 reimbursement credits always apply to reimburse traceable separate contributions to the acquisition of jointly titled property.
CALIFORNIA FAMILY CODE
PRESUMPTION CONCERNING PROPERTY HELD IN JOINT FORM
Family Code Section 2581
For the purpose of division of property on dissolution of marriage or legal separation of the parties, property acquired by the parties during marriage in joint form, including property held in tenancy in common, joint tenancy, or tenancy by the entirety, or as community property, is presumed to be community property. This presumption is a presumption affecting the burden of proof and may be rebutted by either of the following:
(a) A clear statement in the deed or other documentary evidence of title by which the property is acquired that the property is separate property and not community property.
(b) Proof that the parties have made a written agreement that the property is separate property.