Legal Question in Real Estate Law in California

Because you added her name to the deed, she has an ownership interest in the house, is a co-teant with you, and has as much right to possession of the house as you. If she will not agree to sign a deed transferring the property into your name alone, you will have to file a lawsuit against her for partition/quiet title to have a court determine that she has no interest in the property. You should consult with an attorney in your area as soon as possible; the longer you wait to take action to remove her name, the more likely a court may find that she does own an interest.

Mr. Hoffman is right, but he doesn't discuss any legal theory upon which you could get a court to determine that she has no interest in the property. The correct theory to present to a court is called "purchase-money resulting trust." If you can prove by clear and convincing evidence that you paid 100% of the purchase money (i.e., the deposit and down payment) AND that you did not intend to make a gift of a half interest to the girl friend, a court should find that, irrespective of how legal title is held down at the County Recorder's, you are entitled to 100% ownership and that the girl friend is holding her supposed half interest in legal title as an involuntary trustee with you as beneficiary, and that she is under a duty to convey that half interest to you upon your request.

As to the issue of whether your placing her on title was a gift, there is a presumption in English law that, when the couple is merely cohabitating, and not married or engaged, that there is no gift. I believe California cases would likewise hold, but I have not done the research recently. Of course, there may be admissible evidence that she could use to rebut the presumption of no gift at trial. Hopefully, you did not write her any letters saying "OK, honey, I'm making you a gift of a half interest in the new house!"

Please feel free to contact me directly if you'd like to pursue getting her off title. I have handled several cases of this kind, including one I won at the Court of Appeal.