http://www.msn.com/en-us/news/us/officia...ater/ar-AAlAD6W

An excellent reason to have a stockpile of reasonably clean H2O on hand. Some years ago we had a very localized, transient problem. The city employee giving us the news showed up with a small crate of bottled water, and I said "That's OK,we've got plenty." Problem resolved in about 24 hours.

Water is pretty fundamental, as any desert rat can tell you