This is the bare minimum, especially if you live in a climate that is hot and humid. You’d be surprised at how quickly a gallon disappears! Washing face, sanitation, some laundry, drinking, food preparation…water goes fast. Since water is, basically, “free”, don’t scrimp on your water storage. Re-filled 2-liter soda bottles stored under beds, on the floors of closets, behind the couch, will all add up.
Have at least a couple of different ways to purify water. Bleach has a limited shelf life but since it’s so inexpensive and readily available, do keep at least one bottle on hand at all times. Write the purchase date on the bottle, and every six months or so, buy a new one and use the bleach in the older bottle.
It’s also smart to have a larger system that can purify larger amounts of water quickly and smaller portable purifiers for emergency kits, bug out bags, and outdoor activities, such as camping, hunting, and hiking. Some of the brands I’ve used and own are PurifiCup........See the full list at The Survival Mom.com