Judging from our SimCity preview from Gamescom 2012, the first rule of sim civic planning is: Don't put your water tower near your sewage plant. Leah "Corgi" Jackson got her hands on SimCity at the German game show, and brought back many similar pearls of wisdom.
Enjoy a brief excerpt from Leah's SimCity preview:
"I even had to place a water tower in my city to get my Sims fresh drinking water. One of the developers told me that if I would have put the sewage plant and water tower near one another it would have caused a chain reaction of epic proportion. Essentially the pollution from the sewage plant would begin seeping in to the water which was being distributed out in to my city. If my Sims drank this poop water, they'd get sick and be unable to work because of it. Personally, I found this scenario to be completely hilarious and genius at the same time."