I couldn't keep 3 months supply for everyone in my house...not in my little urban patch. I keep 5 gallons on hand for every person, keep two Water Bobs in the house to deploy if there is enough warning (which will give me 200 more gallons), and have scoped out water resources within a reasonable distance from the house...I've got a wheelbarrow, water cans, a Berkey, coffee filters, bleach, smaller backpacking filters, and kids that need a workout.