property tax assessment

I own (no mortgage) a house in el cerrito ca. and wish to add my partner's (we are not married) to the deed of the house. we bought the house in 1998 (230K) and only my name went on the deed. the house is currently worth about 700K. if we add her name to the deed so that she inherits the house if i die are there any federal or state tax implications for her? will the tax base for the house get reassessed to the current value or will her taxes be based on the original purchase price?