house tax reassessment

I own ( no mortgage ) a house in el cerrito ca and wish to add my partners name to the deed of the house. we are not married but have been together for 35 years. i want to add her name to the deed of the house so she inherits it if something happens to me. my question is are there tax implications that she would have to pay if she inherited the house? will the tax base for the house be reassessed? I paid 230K in 1998 and it is currently worth about 700k. are there other tax considerations? thanks

dm