How much water to store for an emergency

The short answer

The standard rule is simple. Ready.gov advises storing at least one gallon of water per person per day, for drinking and sanitation, and keeping enough for several days. For a family of four, three days is 12 gallons. Two weeks is 56 gallons. That is a lot, so build up in steps.

Work out your number

Use this quick table. It uses the one-gallon rule and does not include pets.

Ready.gov says "several days" without giving a number. We suggest three days as your minimum and two weeks as a goal, because some outages and water-system failures last longer than a weekend. That two-week goal is our recommendation, not a government rule.

Some people need more than a gallon. Hot weather, illness, and nursing can all raise your needs. Keep a little extra for cooking and washing hands.

Pets

Ready.gov lists extra food and water for your animals in a basic kit. Small pets need much less than people, and large dogs need more. Ask your vet for a number that fits your pet, then add it to your total.

Choose your containers

You have two easy options.

• Commercial bottled water. Keep it in its sealed original container, in a cool, dark place, as Ready.gov advises. It is the simplest choice.
• Your own containers. Use food-grade containers made for drinking water. Avoid old milk jugs, which are hard to clean and can break down. Large containers hold more and take up less fuss.

A 7-gallon container weighs about 58 pounds when full, so check that you can lift it, or use a smaller size. A hand pump or siphon makes pouring from large containers easier and less messy.

How to fill and store your own containers

1. Wash the container with dish soap and rinse well.
2. Sanitize it. Ready.gov's method is one teaspoon of unscented liquid household chlorine bleach per quart of water. Swish it around, let it sit, then rinse.
3. Fill with clean tap water. If your tap water is from a public system, it is usually already treated.
4. Close tightly and write the date on the container with a marker.
5. Store in a cool, dark place, away from sunlight, heat, and chemicals such as fuel or paint.
6. Replace every six months. Ready.gov says water that is not commercially bottled should be replaced on this schedule. Set a reminder on your phone for spring and autumn, such as the days you change your clocks.

The bathtub backup

If a storm is coming and you have warning, fill a clean bathtub, big pots and spare bottles. Bathtub water is for flushing the toilet, washing and cleaning, not for drinking unless you treat it first. Our guide on making water safe to drink shows how. Keep small children away from a full tub.

Your stored containers are your drinking water.

Treatment as a backup

Stored water covers the first days. If you run low, you need a way to make other water safe, such as rain or tap water during a boil advisory. Purification tablets are cheap, light, and last a long time on the shelf.

Common mistakes

• Storing too little. One gallon a day covers drinking and basic hygiene, but not showers or laundry.
• Using containers that held milk or juice. Residue is hard to remove and can grow bacteria.
• Leaving water in the sun or a hot car. Heat damages plastic and speeds spoilage.
• Forgetting to rotate. Mark the date on every container.
• Not planning for flushing. A bucket of tub water can flush a toilet. See our emergency toilet guide.

Next steps

• Read make water safe to drink so you know what to do when stored water runs out.
• Set up a simple emergency toilet so you do not waste drinking water on flushing.
• Follow the 72-hour blackout plan.
• See the Blackout Kit and Family Kit.