The stories of alcoholic beverages historically being safer to drink than unfermented ones are apocryphal at best; however, as any 17th-century sailor would tell you, the addition of some spirits to potable water that's been sitting around for too long will make it much more palatable. Liquor distillation was originally invented in part for medical purposes, and alcohol can be used as a solvent to dissolve medicinal herbs -- and also to knock out patients during good old-fashioned fallout-shelter surgery. High-proof alcohol can be used as an antiseptic, and it does a great job of cleaning wounds and preventing infection.
To me, the best option is to store emergency food. How much? If you have none, store enough for a few days. If you have enough for a few days, get enough for a week. How much you store depends on what time frame you think you're at risk for having to be completely independent. The early settlers of the southwest liked to store enough food for a whole year and still do to this day!