Here's how to store water for emergencies: keep at least 1 gallon per person per day for 3 days, and a 2-week supply if you can. Unopened bottled water is the safest choice. If you fill your own, use clean food-grade containers, label them with the date, keep them cool and dark, and replace them every 6 months.
The CDC recommends storing at least 1 gallon of water per person, per day, for 3 days, and trying for a 2-week supply if possible. Ready.gov uses the same 1 gallon figure and notes that it covers both drinking and sanitation.
Some people need more. The CDC suggests storing extra for pregnant women, people who are sick, pets, and anyone in a hot climate. Ready.gov adds that children and nursing mothers may need more, and that in very hot weather water needs can double.
Quick math (at 1 gallon per person per day):
1 person: 3 gallons for 3 days, 14 gallons for 2 weeks
2 people: 6 gallons for 3 days, 28 gallons for 2 weeks
4 people: 12 gallons for 3 days, 56 gallons for 2 weeks
Add extra for pets on top of these numbers. Our pet emergency kit guide covers the rest of what animals need.
Store-bought water is easiest. The CDC calls unopened, commercially bottled water the safest and most reliable source of water in an emergency. Keep it sealed in its original container in a cool, dark place, and watch the expiration date.
If you fill your own, the CDC recommends FDA-approved food-grade water storage containers, which you can find at surplus or camping supply stores. If you can't get those, pick a container that:
Has a top that closes tightly
Is made of durable, unbreakable material (not glass)
Has a narrow neck or opening, if possible
Never reuse a container that held toxic chemicals, such as bleach or pesticides.
These are the CDC's steps for sanitizing a container before you fill it:
Wash the container with soap and rinse it completely with water.
Mix a sanitizing solution of 1 teaspoon of unscented liquid household chlorine bleach in 1 quart (4 cups) of water. The bleach label should say it contains 5% to 9% sodium hypochlorite.
Cover and shake the container well, so the solution touches every inside surface.
Wait at least 30 seconds, then pour the solution out.
Let it air-dry before you use it.
Fill it with clean water and close it with a tight lid.
Label it. Write "drinking water" and the date you stored it on each container (CDC).
Store it well. Keep containers somewhere cool, between 50 and 70 degrees F, out of direct sunlight, and away from toxic substances like gasoline or pesticides (CDC).
Replace it. Water you bottled yourself should be replaced every 6 months, according to both the CDC and Ready.gov.
Keep it clean when you use it. If you use a scoop, use a clean one each time, and never scoop water out with your hands (CDC).
Example rotation routine (one way to do it, not an official schedule):
Pick two dates about 6 months apart and put them on your calendar.
On each date, empty and re-sanitize your home-filled containers, refill them, and write the new date on the label.
Check the expiration dates on store-bought water and swap out any that are close.
Recount your household. A new baby, a guest who is staying, or a new pet changes how much you need.
The CDC also suggests keeping a bottle of unscented liquid household chlorine bleach (5% to 9% sodium hypochlorite) with your supplies, for disinfecting water if needed and for general cleaning.
Ready.gov says never ration drinking water unless authorities tell you to. Drink what you need today and look for more for tomorrow. It also says not to drink carbonated or caffeinated drinks in place of water.
The CDC says to use bottled water for drinking, cooking and brushing teeth during an emergency. If you're under a water advisory, our boil water advisory guide explains what each type of notice means and how to boil water correctly.
Look for safe water already in your home. The CDC lists these sources when bottled, boiled or treated water isn't available:
The water heater tank (not a separate tank used for radiator heating, which some older homes have)
Melted ice cubes, if they were made from safe water
Water from the toilet tank, never the bowl, and only if it is clear and has no chemical cleaners added
Liquid from canned fruits and vegetables
Pool and spa water can be used for hygiene and cleaning, but not for drinking. The CDC also says to listen to local officials, and that you may need to shut off your home's main water valve to keep contaminated water out of your pipes.
Treat water from other sources. The CDC's two main methods are:
Boiling: bring clear water to a rolling boil for 1 minute (3 minutes above 6,500 feet), let it cool, and store it in clean, covered containers. Filter cloudy water through a clean cloth, paper towel or coffee filter first, or let it settle.
Bleach: follow the label directions for disinfecting drinking water. For bleach with 5% to 9% sodium hypochlorite, the CDC's chart lists 8 drops per gallon of water. Stir and wait at least 30 minutes before drinking. Use double the amount if the water is cloudy, colored or very cold.
One important limit: the CDC says water that contains fuel, toxic chemicals or radioactive material can't be made safe by boiling or disinfecting. Don't use it.
Replace water you bottled yourself every 6 months. For store-bought water, follow the expiration date and keep it sealed until you need it.
The CDC recommends durable, unbreakable materials instead of glass, ideally food-grade water storage containers with tight lids.
At 1 gallon per person per day, that is 14 gallons per person, plus more for pets, hot weather, illness or pregnancy.
Somewhere cool (50 to 70 degrees F), out of direct sunlight, and away from gasoline, pesticides and other chemicals.
Family Ready: Emergency Plan is a free iPhone app, with an optional Family Ready Plus subscription, that includes an editable emergency kit checklist based on Ready.gov and Get Prepared guidance, with optional sections for children, older adults, pets and rural homes. You can add your water supply to that list and choose a review schedule of 3, 6 or 12 months with optional local reminders, which lines up with refreshing home-filled water every 6 months.
Get Family Ready free on the App Store