I have no idea how high the water table is in the vicinity of my house; that sort of thing varies a lot out here in the East.

I can tell you this; my house is a split-level. The room that is the basement, as measured from the front of the house, is actually ground-level in the back, because the house was built into the side of a hill. We have been here since 1996, and the basement used to be bone dry. Even now, it only leaks after a prolonged rain (like, say, steady rain for most of 24 hours).

Even if you had basements in California, I'd bet you don't get rain in those quantities.