Many couples in California, married or not, hold title of their real property as joint tenants. I find this is mainly the result of not consulting a legal professional when purchasing the property. The property sales paperwork they receive from escrow has a question which asks how the buyers would like their property to vest or how they would like to take title. And not completely understanding the question or repercussions, they often ask and take the advice of someone from the escrow company, title company or their real estate agent, many of whom are not familiar with issues that may arise by holding title in such a manner. Other times, for those currently owning real property, the manner of title is changed because the owner has heard horror stories about the probate process and have been informed that holding property as joint tenants will avoid probate. Which it will, barring any other unusual issues.
Joint tenancy with the right of survivorship is the full proper name, however many jurisdictions allow the forgoing of the phrase "with right of survivorship" in the vesting document. Joint tenants own an undivided equal interest in the property and when one of the joint tenants dies, their interest in that property will pass to the surviving joint tenant or joint tenants, outside of probate by "operation of law." Typically, the only document necessary to reflect the remaining owners of the property, is an Affidavit of Death of Joint Tenant which is filed with the County Recorder's Office. This will show the chain of title and indicate the remaining joint tenants as owners of the property. While owning property as joint tenants or adding a joint tenant to your deed, will avoid probate, it may have unintended consequences.
One such consequence is that a joint tenant cannot leave their interest in the jointly held property by Will or Trust to anyone such as their heirs. This is because your interest in the property will pass to the remaining joint tenants. This is of particular importance in blended family situations. Let's say Husband and Wife meet, both had previous marriages and both have 2 children from those previous marriages. Wife and her two children move into Husband's home and and Husband adds Wife to the title of that home as a joint tenant. Some years later, Husband dies and the property automatically passes to Wife. Husband has a Will that states his children shall receive all of his estate in equal shares. Husband wanted his children to receive the home, or at least his interest in it, however, it now, in its entirety, belongs to Wife, who, in her Will has provided that her 2 children receive all of her assets. Husband probably didn't expect this result and to provide for his own 2 children at his death.
The law pertaining to ownership interests in property can be found in CA Civil Code Section 678-703.
Look for Part II for more consequences of holding title as joint tenants.