When it comes to dividing real property in family law, there are 5 major Real Property Presumptions that parties should be aware of.  They are:

Presumption  Rule Authority
1. General Cp Presumption All real property wherever situated, acquired by a married person during the marriage while domiciled in California is CP. FC § 760
2. “Form of Title” Presumption  Where one spouse takes title to property in his or her name, without reference to the marital relationship or the other spouse, it is presumed that the property is the SP of the spouse holding title. In re Marriage
of Haines (1995) 33 Cal App.4th 277
3. “Joint Title” Presumption Property acquired by the parties during marriage in joint form, including property held in TIC, JT or TBE, or as CP, is presumed To be CP. FC § 2581
4. “Married Woman” Presumption  Property held in (1) married woman’s name alone, or (2) her name & 3rd party, presumption is that it’s her separate property. (Effective only for property acquired before 1975). FC § 803
5. “Undue Influence” Presumption

When title presumption conflicts with presumption of undue influence, Title presumption does not apply. In re Marriage of Haines, Supra, 33 Cal.App.4th at 301-302

Generally, any time there is a transmutation of property, there is a rebuttable presumption of undue influence.

FC § 721(b)

In re Marriag of Matthews(2005) 133 Cal. App.4th 624