For a few months I've been finding these spiders around my house, usually on the ceiling and especially in the bathroom. This picture was taking in a bathtub. Unfortunately the picture quality isn't very good. I live in the San Fransisco Bay Area, area code 94546.
To me it looks like a Ground Spider, Family Gnaphosidae.
I wouldn't know beyond that though.
It definitely appears to be a gnaphosid - see http://tinyurl.com/33nae93 for a species native to your area.
