How to Store Water Long Term and Keep It Safe
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Quick answer: store at least 1 gallon of water per person per day for a minimum of 3 days, and aim for 2 weeks if you can. Use commercially bottled water in its sealed container or clean, food-grade containers. Label and date them, keep them cool and out of sunlight, and replace home-filled water every 6 months. If you must treat water later, boil it for 1 minute (3 minutes above 6,500 feet) or use unscented household bleach as directed below.
Water is the first thing to run short in many emergencies, and it is the one supply you cannot do without for more than a few days. Storms, floods, pipe breaks and power failures can interrupt or contaminate the tap. This guide follows current guidance from the CDC and Ready.gov to show how much water to store, which containers to use, how to keep it safe, and how to treat water when your stored supply runs out.
How much water to store
Both the CDC and Ready.gov recommend storing at least one gallon of water per person per day. The CDC says to store enough for at least three days and, if you can, a two-week supply. That gallon covers drinking, cooking, brushing teeth and basic sanitation. Ready.gov notes that a normally active person needs about three-quarters of a gallon of fluid each day, but needs vary with age, health, activity and climate.
- Children, nursing mothers and sick people may need more.
- Hot weather can double the amount you need.
- Pets need water too, so count them in your total.
- A medical emergency may require extra water.
- Do not ration drinking water unless officials tell you to. Drink what you need today and look for more tomorrow.
As a quick example, a family of four needs 4 gallons a day, so a three-day supply is 12 gallons and a two-week supply is 56 gallons. Work out your own number and store a bit extra.
Choosing containers
The safest and simplest option is unopened, commercially bottled water. Keep it in its original sealed container and watch the expiration date. If you fill your own containers, the CDC recommends food-grade water storage containers, which are designed not to transfer harmful substances into the water. You can find them at camping and surplus stores, and the manufacturer can tell you if a container is food-grade.
If you cannot get a food-grade container, choose one that closes tightly, is made of durable, unbreakable material (not glass) and, if possible, has a narrow opening so you can pour from it. Never use a container that previously held toxic chemicals, such as bleach or pesticides.
Water bricks and jugs
Stackable food-grade water bricks and jerry-can style containers are popular because they stack, are easy to move and often include a spigot. The tradeoff is weight: water weighs about 8 pounds per gallon, so a five-gallon container weighs roughly 40 pounds when full. Choose sizes you can lift safely.
Bathtub bladders
Bladders designed to line a bathtub are a space-saving way to store a large amount of drinking water for a short time when you get advance warning, such as before a storm. Look for products made for drinking water, follow the manufacturer’s instructions for cleaning and filling and treat the water as the product directs. They are meant for short-term storage, not for months.
Barrels
Large barrels hold a lot of water at a low cost per gallon, but a full 55-gallon barrel weighs more than 450 pounds, so it must sit where it will stay, ideally on a stable base. Buy a new food-grade barrel or one that previously held only food-safe contents, clean it thoroughly, and use a proper pump or spigot rather than tipping it. Never use a barrel that held chemicals.
How to clean and fill containers
The CDC gives a simple process for cleaning and sanitizing home storage containers:
- Wash the container with soap and rinse it completely.
- Sanitize it with a solution of 1 teaspoon of unscented liquid household bleach (5% to 9% sodium hypochlorite) in 1 quart (4 cups) of water.
- Cover the container tightly and shake so the solution touches every inside surface.
- Wait at least 30 seconds, then pour the solution out and let the container air-dry.
- Fill it with clean water and close it tightly.
How to store water
- Label each container “drinking water” and write the date on it.
- Replace water you filled yourself every 6 months. The CDC and Ready.gov both give this guidance.
- Keep containers in a cool place, ideally 50 to 70 degrees Fahrenheit, away from direct sunlight.
- Store them away from gasoline, pesticides and other toxic substances.
- When you take water out, use a clean scoop or pour it. Do not scoop with your hands or touch the inside of the container.
For commercially bottled water, follow the expiration date on the label.
Other water sources and what to treat
When your stored water runs low, you may need to use water of uncertain quality. Ready.gov says to drink water you know is not contaminated first, and to treat suspicious water, such as cloudy tap water or water from streams and ponds, before use. The CDC says never to use water from radiators or boilers that are part of a home heating system for drinking, cooking or hygiene.
Water that contains fuel, toxic chemicals or radioactive materials cannot be made safe by boiling or disinfecting. If you suspect that kind of contamination, use bottled water or another source and contact your health department. Pool and hot tub water contains chemicals and is not meant for drinking, so use it for flushing toilets and cleaning if officials say it is safe to use that way. Rainwater from a barrel or cistern should also be treated before drinking, and local rules on collecting rainwater vary, so check yours.
How to treat water
If the water is cloudy, first let it settle or strain it through a clean cloth, paper towel or coffee filter, then draw off the clear water.
Boiling
The CDC calls boiling the best way to kill germs. Bring clear water to a rolling boil for 1 minute, or 3 minutes at elevations above 6,500 feet, then let it cool and store it in clean, sanitized containers with tight covers. Pouring it back and forth between two containers improves the flat taste. If you lose power, see how to boil water without electricity.
Bleach
Use only regular, unscented household bleach that contains 5% to 9% sodium hypochlorite, and avoid scented, color-safe or splash-less products. For bleach in that range, the CDC says to add 8 drops per gallon of clear water, 2 drops per quart or a little less than 1/8 teaspoon per gallon. If the water is cloudy, murky, colored or very cold, double the amount. Stir well and let it stand at least 30 minutes before drinking. Store it in clean, sanitized containers with tight covers. Bleach is less effective than boiling against some parasites such as Cryptosporidium and Giardia.
Older versions of this article suggested different amounts of bleach. Follow the current CDC figures above and the instructions on your bleach label.
Filters, tablets, UV and distillation
Portable filters do not remove viruses. The CDC says a filter needs an absolute pore size of 0.3 micron or smaller to remove bacteria and 1 micron or smaller to remove parasites, and recommends adding a chemical disinfectant after filtering. Chlorine dioxide tablets can kill Cryptosporidium when used according to directions, while iodine and chlorine tablets will not. People who are pregnant or have thyroid problems should avoid water treated with iodine. Ultraviolet units and solar disinfection only work well in clear water. Distillation removes microbes plus heavy metals, salts and most chemicals. For more on methods, see our guides on purifying water from any source and why you should filter your water in an emergency.
Water storage in winter
Water expands as it freezes and can crack rigid containers. If you store water in a garage, shed or outdoors in a cold climate, read our guide to keeping emergency water from freezing outside. Thawed water that has been in a damaged container should be inspected and treated before drinking.
Frequently Asked Questions
How long can I store water?
The CDC and Ready.gov recommend replacing water you fill yourself every 6 months. For commercially bottled water, follow the date on the container.
How much water should I store per person?
At least one gallon per person per day, for at least three days, with two weeks as a better goal. Store more for hot climates, pets, pregnancy or illness.
Do I need to treat tap water before storing it?
If your tap water is municipally treated and safe, storing it in clean, sanitized, food-grade containers is the standard approach. If you are unsure about its safety, treat it first. Follow your local health department’s advice.
Why does stored water taste flat or odd?
Boiled or long-stored water loses dissolved oxygen. The CDC suggests pouring it back and forth between clean containers and letting it stand for a few hours, or adding a pinch of salt per quart.
Do I need to boil stored water before drinking it?
Not if it was safe and sealed in clean containers within six months. If you have any doubt about the water or the container, treat it before use.
Can I drink pool water in an emergency?
No. Pool water contains chemicals and is not meant for drinking. Use it for sanitation if local officials say it is safe for that.
Bottom line
Start with bottled water, add food-grade containers as your budget allows, label and date everything and set a reminder to rotate every six months. Learn how to boil and disinfect water before you need to. A small amount of planning now makes a big difference in an emergency.
