Sure if you’re making sure to always keep more than a week’s worth of food in the house, and it seems that loads of people aren’t, hence the above mentioned govt campaign.
Food is fine, assuming you have the cash to fill your cupboards. Water is awkward as who buys bottled water for use in the home? Canned water lasts a lot longer but isn't widely available in the same way.
That's called doing the weekly shop, isn't it?