You can deed the property to the both of you and create a joint tenancy, which requires the "unities" of time, title, interest and possession. You don't indicate whether you are selling or gifting the interest. There may be an increase in the secured property taxes if you are selling the interest and the value of the one-half interest being transferred is greater than it was at the time you acquired the property.
This answer does not constitue legal advice, nor does it creat an attorney/client relationship. If you are seeking legal advice upon which you intend to rely, you should hire competent cousel familiar with this area of the law in your locale.
In Texas you can deed all of your interest to both of you as JTWROS. I bet it is the same in California.
Actively practicing law in Texas. Inactive licenses in Arizona and Georgia. All answers are general in nature and no attorney/client relationship exists in this forum.