For emergency preparations, it's suggested that you have 1 gallon of water/person per day up to 7 days. We live in the topics, and I'm always concerned that we will run out of water during those hot months aka Hurricane Season.
coffee can car emergency kit. my mom made me one a long time ago. it's in my trunk and has matches, candle (to put inside the can and burn if stranded), meal replacement bars, and other items. She put a neon orange ski cap over the top of the can ;)