I discovered today that our monthly water bill (from the San Francisco Public Utilities Commission) includes a graph of our water usage over the last year.  It's pretty fascinating trying to correlate it to events; for example, we used a lot of water last November, the month after Penelope was born.
I think I'm going to experiment with bringing our water usage down to see how much of an effect I can have, now that I'll have this data on a monthly basis.
But here's what I'd like next: a comparison chart (anonymous, of course) to everyone in my neighborhood; my city; my state; and so on. That way, I can see how we compare to other people in our area, and it can become a competition. Give me stats, charts, and graphs showing us how we compare, and you'll see our water usage drop!
 Considering that they're pushing water conservation, I'll bet this isn't a coincidence.