At a small but growing number of sustainably inclined Bay Area restaurants, bottled water has become as much of an outcast as farmed salmon and out-of-season tomatoes. Instead of bottled water, diners now are served free carafes of -- gasp! -- tap water. It's filtered and comes still or sparkling, fizzed up by a soda-fountain-style carbonating machine. Incanto, in San Francisco's Noe Valley, and Poggio, in Sausalito, pioneered the trend four years ago. But for several years, no other restaurants wanted to give up popular -- and profitable -- bottled water. Then Nopa, the San Francisco North of Panhandle hot...