A lot of places in California have water tables that are too low. Basements did not work out well for that, especially in the winter.
True. I had one in town growing up and when it was 110 out I could go down to the basement and relax. I don't think it ever got over 80 on the hottest days down there. Never had a flooding issue either after I built a window for the "vent" to keep the rain out.
