The same here. At home I drink tap water, but filtered or boiled first. It helps remove the impurities and the noticeable chlorine taste. But San Francisco's tap water is pretty decent and I'm fine with drinking it straight from the tap at someone else's home. With the exception of my best friend's former residence who lives right over a still contaminated former toxic waste dump [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CC4QFjAA&url=http%3A%2F%2Fen.wikipedia.org%2Fwiki%2FBayview-Hunters_Point%2C_San_Francisco&ei=9PMrUo69A8abiALXu4DoBQ&usg=AFQjCNGlesiHZ_T3nPljPsG1DC0naFa_WA&sig2=gTpm33rHvvAfxa28o03AQw&bvm=bv.51773540,d.cGE] and whose tap water comes out brown and with grainy sediment.Dirty Hipsters said:Yes, I drink tap water, but after I filter and boil it first. The water in my area isn't bad or anything, but I've just learned not to trust tap water anywhere.
As far as bottled water goes, I hate it. It always has this little bit of a plastic aftertaste that I just can't stand, so I much prefer my tap water over it.
I lived in Petaluma, CA for two years and their tap water was gag reflex inducingly awful. There was this overwhelming flavor of ammonia and sulfur, but after two years I got used to the taste but could still taste it. Every one else new or visiting would nearly spit out their drink.
San Diego's was pretty bad the last time I was there.
I found that the plastic after taste in bottled water usually comes with really old bottles. When that's the case you're smart for disliking it, unless you prefer some dioxin in your drink.