California Code, Probate Code - PROB § 5610

(a) Except as provided in subdivision (b), “real property” means either of the following:

(b) “Real property” does not include a parcel of agricultural land that is greater than 40 acres in size. For the purposes of this subdivision, “agricultural land” means land that is designated for agricultural use by law or by a document that is recorded in the county in which the land is located.

(c) The definition of “real property” shall be construed pursuant to the circumstances that existed on the execution date shown on the revocable transfer on death deed.