How to Store Water for Emergencies: How Much, Which Containers, and How Long It Lasts

When a hurricane is in the forecast, bottled water is often the first thing to vanish from store shelves. When a water main breaks or a flood contaminates a city’s supply, it can be days before the tap is safe again. The fix is simple and cheap if you do it before the emergency: store clean water at home, in the right containers, in the right place, and know how to make more water safe when your supply runs out.

This guide pulls together the official advice from the CDC, the EPA, FEMA’s Ready.gov and the American Red Cross: how much to store, which containers to use and which to avoid, how to clean them, how long stored water lasts, where to find hidden water in your home, and exactly how much bleach to use when you have to disinfect water yourself.

How much water to store

The standard rule is <strong>at least 1 gallon of water per person per day</strong>. The CDC says to store that for at least 3 days and to aim for a 2-week supply if you can. The American Red Cross frames it the same way: a 3-day supply for an evacuation kit and a 2-week supply for home. That gallon is not all for drinking. Ready.gov notes that a normally active person needs about three-quarters of a gallon of fluid a day, and the rest covers cooking, brushing teeth and basic hygiene.

Plan for more than the minimum if any of these apply. Ready.gov says children, nursing mothers and sick people may need more water, a medical emergency might require extra, and in very hot temperatures water needs can double. The CDC adds pregnant women and pets to the list. Ready.gov’s pet guidance is to keep a water bowl and several days of water for each animal in its own kit.

Household	3 days (minimum)	2 weeks (recommended)
1 person	3 gallons	14 gallons
2 people	6 gallons	28 gallons
Family of 4	12 gallons	56 gallons
Family of 4 in a heat wave (needs can double)	Up to 24 gallons	Up to 112 gallons

Two rules from Ready.gov matter once an emergency starts. Never ration drinking water unless authorities tell you to: drink what you need today and look for more for tomorrow. And don’t drink coffee, soda or alcohol in place of water, because caffeine and alcohol increase the amount of water your body needs.

Buy it or fill it yourself

The easiest option is commercially bottled water. 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 or "use by" date. Be Ready Utah, the state’s preparedness program, notes that the recommended two- to three-year shelf life on bottled water is about the bottle breaking down, not the water going bad, so rotate it into everyday use and replace it.

Bottled water is convenient but takes a lot of space and costs more per gallon than tap water. Filling your own containers is cheaper and works well as long as you start with food-grade containers and clean them properly.

Choosing a container: what to use and what to avoid

The CDC recommends FDA-approved food-grade water storage containers, which will not transfer toxic substances into the water. If you can’t get one, the CDC says the container should have a top that closes tightly, be made of durable, unbreakable material (not glass), and ideally have a narrow neck so you can pour without dipping into it.

In practice, that usually means high-density polyethylene. Be Ready Utah calls food-grade HDPE containers, marked with a "2" in the recycling triangle, the standard way to store water long term, and suggests dark, solid colors that block light. Oregon State University Extension recommends food-grade buckets, carboys or drums stamped with a PETE (#1) or HDPE (#2) code. Clean two-liter soda bottles, which are PETE, are also fine: the Red Cross recommends them as the reusable option.

Avoid these:

<strong>Milk and fruit juice jugs.</strong> The Red Cross says milk protein and fruit sugars cannot be adequately removed and give bacteria a place to grow. Oregon State Extension adds that milk jugs are made of a thin plastic designed to break down, so they can start to leak.

<strong>Cardboard cartons and glass.</strong> Cartons leak and aren’t designed for long-term storage; glass is heavy and can break, according to the Red Cross.

<strong>Anything that ever held chemicals.</strong> The CDC says never to use containers that held liquid or solid toxic chemicals such as bleach or pesticides. Be Ready Utah puts it bluntly: you can never get them clean enough for drinking water.

Container	Typical size	Good for	Watch out for
Sealed commercial bottled water	0.5 liter to 1 gallon	No prep, easy to carry, safest per CDC	Takes space; check the date and rotate
Two-liter soda bottles (PETE #1)	2 liters	Free, airtight, easy to stash	Wash and sanitize first; never milk or juice jugs
Stackable food-grade jugs or bricks (HDPE #2)	3.5 to 7 gallons	Portable, stack in closets and under beds	About 29 lb (3.5 gal) to 58 lb (7 gal) when full
55-gallon food-grade drum (HDPE #2)	55 gallons	Most water per square foot	About 480 lb full, needs a pump or siphon, can’t be moved
Bathtub bladder	Up to about 100 gallons	Filling right before a storm	Short-term only; buy before the forecast, not during
Milk jugs, cartons, glass, old chemical containers	Any	Nothing; avoid	Leaks, bacteria, breakage or chemical residue

How to clean and sanitize containers

New or reused, every container should be washed and sanitized before you fill it. This is the CDC’s method:

1. Wash the container with soap and rinse it completely with water.

2. Mix a sanitizing solution of <strong>1 teaspoon of unscented liquid household chlorine bleach in 1 quart (4 cups) of water</strong>. Use bleach that contains 5% to 9% sodium hypochlorite.

3. Pour it in, cap the container tightly and shake it well so the solution touches every inside surface.

4. Wait at least 30 seconds, then pour the solution out.

5. Let the empty container air-dry (or rinse it with safe water), then fill it with clean water and cap it tightly.

Use plain bleach only. Ready.gov and the EPA both say not to use scented, color-safe or bleaches with added cleaners. Be Ready Utah also suggests filling from a drinking-water-safe hose, sold for RVs and boats, rather than a garden hose, which can add contaminants and a rubbery taste.

Treating tap water before you store it

If your water comes from a public utility that treats it with chlorine, you don’t need to add anything. The FEMA and Red Cross guide <em>Food and Water in an Emergency</em> says chlorinated tap water needs nothing else to keep it clean, and Be Ready Utah advises against "re-treating" municipal water. Fill the container to the top, cap it without touching the inside of the cap, and you’re done.

Well water and other untreated sources are different. Both the Red Cross guide and Be Ready Utah say to treat that water before you store it, using the bleach doses in the disinfection section below, because whatever is in it can multiply during months in storage.

Label it and rotate it

Label each container "drinking water" with the date you filled it, the CDC advises, and <strong>replace self-filled water every 6 months</strong>. For store-bought water, follow the expiration date. An easy habit is to swap your stored water when you change your clocks in spring and fall, and use the old water for plants or cleaning.

Where to store it

The CDC’s storage rules are short: keep containers somewhere with a cool temperature (50°F to 70°F), out of direct sunlight, and away from toxic substances such as gasoline or pesticides. Each one has a reason.

<strong>Cool and dark.</strong> Be Ready Utah explains that sunlight, and even artificial light, makes plastic brittle over time and lets algae grow, while heat speeds the growth of bacteria and algae. Freeze-thaw cycles can loosen seals and crack containers.

<strong>Away from fuels and chemicals.</strong> Polyethylene is slightly permeable, so vapors from gasoline, solvents or pesticides stored nearby can seep through container walls into the water. A garage shelf next to the lawn mower fuel is a poor spot.

<strong>Off bare concrete.</strong> Be Ready Utah recommends setting containers on a pallet or a couple of 2x4s rather than directly on concrete, so air can circulate and condensation or spills can dry instead of feeding mold.

<strong>In more than one place.</strong> If one room floods or a wall comes down, water stored elsewhere is still usable. Keep some in small containers you can carry to the kitchen or bathroom, even if most of your supply is in large drums.

Remember the weight. Water is about 8.3 pounds per gallon, and a full 55-gallon drum weighs roughly 480 pounds, so put big containers where they will stay and plan how you will get water out of them, typically with a siphon or drum pump.

Hidden water already in your home

If an emergency catches you without enough stored water, you may have more than you think. The FEMA and Red Cross guide lists the water in your hot-water tank, your pipes and your ice cubes as safe sources. A typical tank water heater holds dozens of gallons.

<strong>Protect it first.</strong> If you hear reports of broken water or sewage lines, or local officials warn of a problem, close your home’s main water valve so contaminated water can’t flow in. Learn where that valve is now.

<strong>Water heater.</strong> Make sure the electricity or gas is off, then open the drain at the bottom of the tank. To get the water flowing, turn off the water intake valve at the tank and turn on a hot-water faucet. Refill the tank before turning the power or gas back on; if the gas was shut off, the guide notes that a professional will need to turn it back on. Let the water cool before you handle it.

<strong>Pipes.</strong> Turn on the highest faucet in the house to let air into the plumbing, then collect water from the lowest faucet.

<strong>Ice.</strong> Let ice cubes melt in a clean container. The EPA also lists ice and water drained from the hot water tank or pipes as backup sources, and says to treat water from any uncertain source before you drink it.

<strong>What not to use.</strong> The FEMA and Red Cross guide says not to use water from toilet flush tanks or bowls, radiators, waterbeds, or swimming pools and spas. The CDC adds that water from radiators or boilers in a home heating system should never be used for drinking, cooking or hygiene. Toilet tanks are especially risky if you use in-tank cleaning tablets: the CDC warns that water containing fuel or toxic chemicals can’t be made safe by boiling or disinfecting. Never drink floodwater.

How to make water safe in an emergency

When your stored water runs out and you have to use water of uncertain quality, start by letting it settle or straining it through a clean cloth, paper towel or coffee filter if it’s cloudy. Then use one of the methods below. The CDC calls boiling the best way to kill germs in water.

Boiling

Bring clear water to a rolling boil for <strong>1 minute</strong>, let it cool, and store it in clean, sanitized containers with tight covers. At high elevation, boil for <strong>3 minutes</strong>. The CDC sets that cutoff at 6,500 feet, while the EPA uses 5,000 feet (1,000 meters), so if you live anywhere in between, 3 minutes covers both. Boiled water tastes flat; the EPA suggests pouring it back and forth between clean containers or adding a pinch of salt per quart.

Unscented household bleach

If you can’t boil, you can disinfect with plain, unscented liquid chlorine bleach. Check the label for the sodium hypochlorite percentage, and follow the label’s own instructions for disinfecting drinking water if it has them. The EPA adds that the bleach should be fresh or stored at room temperature for less than a year. Add the dose below, stir well and <strong>let it stand at least 30 minutes</strong> before drinking. <strong>Double the dose if the water is cloudy, murky, colored or very cold.</strong>

Amount of water	CDC: bleach with 5% to 9% sodium hypochlorite	EPA: 6% bleach	EPA: 8.25% bleach
1 quart or liter	2 drops (0.1 mL)	2 drops	2 drops
1 gallon	8 drops (½ mL, a little less than ⅛ teaspoon)	8 drops	6 drops
5 gallons	40 drops (2½ mL, or ½ teaspoon)	Not listed	Not listed
8 gallons	Not listed	⅔ teaspoon	½ teaspoon

After 30 minutes the water should have a slight chlorine smell. If it doesn’t, the EPA says to repeat the dose and wait another 15 minutes. If the chlorine taste is too strong, pour the water between clean containers and let it stand for a few hours.

Tablets, filters and what each one misses

No single method removes everything, so it helps to know what each one does. According to the CDC, chemical disinfectants such as bleach, iodine and chlorine dioxide tablets kill bacteria and viruses, but bleach and iodine don’t work well against the parasites Giardia and Cryptosporidium. Chlorine dioxide is the strongest tablet option: the CDC’s emergency guidance says it kills Cryptosporidium when the instructions are followed exactly, and its hiking guidance calls it somewhat effective, so filtering first is still safest. The CDC travel health guide notes that chlorine dioxide can need several hours of contact time. The EPA says to follow each tablet’s label, because products differ in strength and wait time. The CDC also says people who are pregnant, have thyroid problems or are sensitive to iodine should avoid iodine-treated water, and no one should drink it for more than a few weeks.

Portable filters work the other way around. The CDC says a filter with an absolute pore size of 1 micron or smaller, or one certified to NSF Standard 53 or 58 for cyst reduction, removes parasites but not viruses or all bacteria. A filter rated 0.3 micron or smaller removes bacteria and parasites but still not viruses. Only reverse osmosis removes parasites, bacteria and viruses, and it also removes salt. Filter first, then disinfect, and you cover all three.

Some filters are sold as "purifiers." The CDC’s travel health guide explains that manufacturers making that EPA claim must show their products remove at least 99.9999% of bacteria, 99.99% of viruses and 99.9% of Cryptosporidium or Giardia, but the EPA does not independently test those claims.

Finally, the EPA notes that boiling and disinfection do not remove heavy metals, salts or most other chemicals. Ready.gov says distillation, collecting the steam from boiling water as it condenses, removes those as well as germs. That is also the only way the FEMA and Red Cross guide allows for using seawater.

Method	Bacteria	Viruses	Giardia and Cryptosporidium	Chemicals, metals, salt
Boiling (1 minute)	Yes	Yes	Yes	No
Unscented bleach	Yes	Yes	Giardia partly, Crypto no	No
Chlorine dioxide tablets (follow label time)	Yes	Yes	Yes, with full contact time	No
Filter, 1 micron or cyst-certified	Not all	No	Yes	No
Filter, 0.3 micron or smaller	Yes	No	Yes	No
Filter plus disinfectant	Yes	Yes	Yes	No
Distillation	Yes	Yes	Yes	Yes

Apartments, small spaces and cars

You don’t need a basement full of barrels. In an apartment, stackable 3.5- to 7-gallon jugs fit in closet floors, under beds and behind couches, and two-liter bottles slip into gaps in cabinets. Spread the weight around rather than stacking hundreds of pounds in one spot, and keep at least a few gallons near the door in carry-sized containers in case you have to leave.

A bathtub bladder can add a large short-term supply when you have warning, such as a hurricane forecast. It is a food-grade liner that sits in the tub and is filled from the faucet, with a pump or spout to get the water back out. It is a supplement for a known storm, not a replacement for stored water, because you need the plumbing to still work when you fill it. For a sense of what a major hurricane can do to a coastal city, read how Galveston raised itself after the deadliest storm in U.S. history.

For your car, Ready.gov recommends keeping an emergency supply kit in the vehicle, and its basic kit starts with water. Sealed commercial bottles are the best choice because a parked car gets very hot in summer and can freeze in winter. Be Ready Utah warns that temperature extremes speed bacteria and algae growth and that freezing can crack containers, so swap car water more often than the water in your house, and don’t fill containers to the brim if they might freeze.

Seasonal forecasts can help you decide when to top up. A strong El Niño, for example, can shift winter storm patterns across the U.S.

Emergency water checklist

Task	Details
Calculate your target	1 gallon per person per day; 3 days minimum, 2 weeks if possible; more for heat, nursing, illness, pregnancy and pets
Buy or gather containers	Food-grade HDPE (#2) jugs or drums, sealed bottled water, or clean two-liter soda bottles; no milk jugs or chemical containers
Clean and sanitize	Soap and water, then 1 teaspoon unscented bleach per quart; shake, wait 30 seconds, drain, air-dry
Fill	Chlorinated tap water as is; treat well water first; use a drinking-water-safe hose
Label	"Drinking water" plus the date filled
Store	50°F to 70°F, dark, off bare concrete, away from fuels and chemicals, in more than one spot
Rotate	Self-filled water every 6 months; bottled water by its date; car water more often
Keep treatment supplies	Unscented bleach (5% to 9%, less than a year old), a dropper, coffee filters, a pot for boiling, tablets or a filter
Know your hidden water	Find the main water shutoff and the water heater drain valve before you need them

Emergency water FAQ

How long does stored tap water last?

Federal guidance says to replace self-filled water every 6 months. Properly treated water doesn’t spoil on a fixed date, but rotating it limits the chance of contamination from containers, caps or handling.

Can I drink water from my water heater?

Yes, the FEMA and Red Cross guide lists the hot-water tank as a safe source. Turn off the power or gas first, let the water cool, and treat it if you have any doubt about its quality.

How many drops of bleach per gallon of water?

For clear water, the CDC says 8 drops per gallon of bleach with 5% to 9% sodium hypochlorite; the EPA says 8 drops of 6% bleach or 6 drops of 8.25% bleach. Double it for cloudy or very cold water and wait at least 30 minutes.

Is it safe to store water in milk jugs?

No. The Red Cross says milk proteins can’t be fully removed and let bacteria grow, and Oregon State University Extension notes milk jugs are made to break down and can leak.

Does boiling remove chemicals?

No. Boiling kills germs but does not remove heavy metals, salts, fuel or most chemicals. Only distillation removes those, and water contaminated with fuel or toxic chemicals should not be used at all.

Boiling water looks simple, but there is surprising physics in a pot on the stove, including the Leidenfrost effect that lets droplets skate on a hot pan.

Further reading