As the winter rain season (and the power outages that it occasionally causes) approaches, I've been touching up my emergency preps.
At this time every year, I refresh my first line of defense, which is a stack of 60 1-gallon water jugs from the Whole Foods in town. Total cost was slightly over $60 (roughly $1 per gallon).
These will be the first water stores we tap during an emergency. Each person in the family will get 1 jug per day if we're ever without running and/or potable water for a stretch. That's a little more than 2 week's supply.