Nobody tells restaurants to only serve water on request - as you pointed out, the amount of water that a human can drink is insignificant compared to other water use; a 7 gallon/26 liter toilet flush could keep you alive for two weeks. Restaurants hate serving water, as it reduces the amount of (paid for) food/beverages that you will order.

The drought is a great excuse for them to find way to make more money. It's pretty clever, actually.

Actually this is common during drought periods[1]. My intuition is this is a "drop in the bucket" (ha ha) in terms of water savings. So I think it's done for the symbolism. The government wants to let everyone know that they're "doing something" to solve the problem!

As you point out, there are so many other activities that use a lot of water. I notice that you responded to another comment where someone mentioned that Palm Springs was using 736 gallons per residential customer per day. Incredible.

Oh, and BTW, for those not from the area, there really is a serious drought in California. But most of the locals don't seem very concerned about it.

[1] http://www.npr.org/blogs/thesalt/2014/02/05/271997854/califo...