My Google-Fu has always sucked, but now it's failing me entirely. My story takes place about modern times (+/- a year or two from now), but it's set in a world about 12 years after some plague decimated most of humanity. There's not much left as far as technology goes, but what I'm hung up on is the water system in the San Francisco Bay area. I've tried Googling it, and my results were all for some improvement plan circa 2005. I do know that it's "gravity fed," but I'm not even really sure what that means. There wouldn't happen to be an engineers out there, would there?