John McAdams is calling this Bay Area snobbery:

In March, the San Francisco Chronicle spotted a hot new food trend in the Bay Area. Instead of offering diners a choice of still or sparkling bottled water with their (inevitably) locally grown delectables, trendoid restaurants such as Incanto, Poggio, and Nopa now offer glorified tap water. Sustainable-dining pioneer Chez Panisse has also joined the crowd, tossing Santa Lucia overboard for filtered municipal water, carbonated on-site. The reason: It takes a lot of energy to create a bottle of water and ship it from Europe to California. And so of-the-moment bistros can boost their enviro cred by giving away tap water instead of selling promiscuously marked-up bottled water.

To which John says:

Thus the elitists moan and complain when people they consider their cultural inferiors - Southerners, conservative Christians, blue collar workers, people who live in Texas — get uppity and elect a President or Congress of whom the elitists disapprove. How dare people who drink tap water (or Miller Beer or iced tea) think they can govern the nation!

Apparently John never lived in California.  Having lived in Santa Barbara (called the California Riviera in case you think it's not as elitist as San Francisco) for 12 years, I can attest to how much of a sacrifice this really is.  All our water came from local reservoirs, the largest of which is Cachuma in the mountains.  Pretty much every family on our block had bottled water (like Culligan) delivered to their homes, and only used straight tap water only for dishes, laundry, and maybe making coffee.  The joke in Los Angeles is that they didn't trust air they couldn't see.  The joke in Santa Barbara was that we didn't trust water we couldn't see.

If you filled a clear glass with tap water out of the faucet, you could hold it up to the light and see little particulates and sediment floating in the water.  Seriously.  We take water for granted in Wisconsin, and have a huge source of it just to the east.  In California, water is a lot more scarce, and quality often suffers.  Granted it won't kill you by any means (it's not like Mexico), but even the non-elitist snobs among us drank bottled.

So why are these restaurants talking about how much more environmentally friendly their decision is?  Is it because it's elitist and snobbish?  No... it's just good marketing.  They're taking advantage of a craze right now to sell more product, in an area where drinking tap water really is something you only do if you're desperate.