If you do things right you can make sure to keep it your separate property.
I highly recommend that you talk to an real estate attorney in order to make sure that it remains your separate property.
Otherwise, you could "accidentally" do the wrong thing and create a "mess"!
I might not cover every possible way that you could "slip up" so do not rely on this blog to cover every possible way in which to convert separate property into community property!
It could cost you a lot of money and heart-ache later down the road!
Spend a little now & save a lot later!
If you put your spouse's name on the title, it becomes community property.
If you use community funds to pay the taxes or make improvements, then you are asking for trouble!
If you re-finance or take out a loan on the property, it becomes community property.
You might want to have an attorney prepare a pre-nup. (and a post nup.) agreement for both of you to sign. These legal documents must be done absolutely properly and both of you must make full disclosure or they are not valid.
I do not recommend using the "do it yourself" kits that are sold on t.v. and on the radio! (I would definately avoid the kits sold at office supply stores - they clearly state on the back of the box that they do not include the state appropriate forms -- so they are a complete waste of money.)
Please talk to a real estate attorney and make sure to do it right!