How much water should you store for 72 hours?

Store at least 3 litres (0.8 US gal) of drinking water per person per day, which is 9 litres (2.4 US gal) per person for 72 hours. That covers drinking and simple food preparation. If you also want to wash and cook comfortably, plan for up to 10 litres (2.6 US gal) per person per day.

By Richard Wildmark Sousa, EditorPublished 30 October 20268 min read

In short

Minimum: 3 L (0.8 US gal) per person per day, 9 L (2.4 US gal) for three days.

A family of four needs 36 L (9.5 US gal): about two dozen 1.5 L bottles.

Add extra for hot weather, illness, breastfeeding, babies’ formula and pets.

Bottled water keeps until its date; refresh tap water you bottle yourself every six months.

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The short answer: 3 litres per person per day

Most civil-protection agencies converge on a simple rule: keep about 3 litres (0.8 US gal) per person per day. The Netherlands’ Denk vooruit campaign and Sweden’s In case of crisis or war brochure both use 3 litres a day. The UK government asks for 3 litres a day for drinking and notes that cooking and washing need more. In the United States, Ready.gov (FEMA) recommends one gallon, about 3.8 litres, per person per day.

For a 72-hour kit that means 9 litres (2.4 US gal) per person. It sounds like a lot, but it is just six standard 1.5-litre bottles.

How much water for your household?

People	Minimum for 72 h (3 L/day)	Comfortable for 72 h (10 L/day)	In 1.5 L bottles
1 person	9 L (2.4 US gal)	30 L (7.9 US gal)	6 bottles
2 people	18 L (4.8 US gal)	60 L (15.9 US gal)	12 bottles
3 people	27 L (7.1 US gal)	90 L (23.8 US gal)	18 bottles
4 people	36 L (9.5 US gal)	120 L (31.7 US gal)	24 bottles
5 people	45 L (11.9 US gal)	150 L (39.6 US gal)	30 bottles

The “comfortable” column follows the UK government and British Red Cross figure of around 10 litres a day once you include cooking and basic hygiene. The World Health Organization’s emergency guidance gives a similar picture: 2.5–3 litres a day for drinking and food, and roughly 7.5–15 litres a day for survival-level drinking, cooking and hygiene combined.

What official agencies recommend

Source	Daily amount per person	Period to plan for
European Commission	No fixed litres; “essential supplies”	At least 72 hours
Netherlands (Denk vooruit)	3 L (0.8 US gal)	72 hours
Sweden (MSB/MCF)	At least 3 L (0.8 US gal)	At least one week
Germany (BBK)	2 L (0.5 US gal): 1.5 L to drink, 0.5 L to cook	Ideally 10 days, 3 days as a start
United Kingdom	3 L (0.8 US gal) to drink; ~10 L (2.6 US gal) with cooking and washing	3 days
United States (Ready.gov)	1 US gal (3.8 L)	Several days

The differences are smaller than they look. Germany counts 2 litres for drinking and cooking only; the 3-litre figure used elsewhere leaves a little margin for washing hands and brushing teeth. If you live somewhere hot, or someone in the house is ill, pregnant or breastfeeding, plan on the higher numbers.

Who needs extra water?

Hot weather. In a heatwave adults can need noticeably more than 3 litres a day. If your summers regularly pass 35 °C (95 °F), store at least 4–5 litres (1.1–1.3 US gal) per person per day for that season.
Babies. Ready-to-feed formula needs no water at all, which is why the UK government recommends it for emergency kits. If you rely on powdered formula, add water for mixing and for boiling. See our baby kit.
Illness and medical needs. Fever, diarrhoea and some medicines increase fluid needs. Keep a few sachets of oral rehydration salts.
Pets. The Dutch government suggests 50 ml per kilogram of body weight per day. A 20 kg (44 lb) dog needs about 1 litre (34 fl oz) a day, 3 litres (0.8 US gal) for 72 hours.

Which containers are best?

For most homes, sealed supermarket bottles are the simplest answer: they are clean, dated, easy to carry and easy to rotate. Add one or two larger containers if you have the space.

Product	Best for	Key spec	Buy
Food-grade 10 L (2.6 US gal) container	Most homes	Weighs ≈ 10 kg (22 lb) full; stackable	Check price on Amazon
20 L (5.3 US gal) jerrycan with tap	Families, houses with storage	≈ 20 kg (44 lb) full: store where it will be used	Check price on Amazon
Collapsible container with tap	Flats, collecting emergency water	Folds flat when empty	Check price on Amazon
Bathtub water bladder	Filling up when a cut is announced	Holds roughly a bathtub’s worth	Check price on Amazon

We don’t list prices because they change often. Use the button to see the current price on Amazon.

Whatever you choose, keep a collapsible container or clean bucket with a lid. During long outages water companies in the Netherlands and Sweden hand out emergency drinking water from tanks, and you bring your own container.

How to store water safely

Use clean, food-grade containers that close tightly. Never reuse containers that held chemicals, and avoid milk or juice cartons, which are hard to clean.
Fill from a clean tap with clean hands, close the container straight away and write the date on it.
Keep it cool and dark, off the floor of a garage where fuel or chemicals are stored.
Refresh self-filled water every six months, as the Dutch government advises. Use the old water on plants.
Rotate bottled water by drinking the oldest bottles and replacing them.
Freeze a few bottles. Sweden’s brochure suggests keeping plastic bottles in the freezer: they act as ice packs during a power cut and become drinking water when they melt. Leave space at the top so they don’t split.

Water you already have at home

If a cut is announced, or the power fails and you live on an upper floor, fill containers, pans and the bath straight away. Pumps that push water up tall buildings need electricity, so pressure can drop quickly. Other hidden reserves:

The hot water cylinder or boiler tank, if you have one (switch off the heating element or boiler first).
Water left in pipes: open the lowest tap in the house.
Ice cubes and frozen bottles.
The toilet cistern (not the bowl): fine for flushing and cleaning, but treat it before drinking.

If your stored water runs out

Boiling is the most reliable way to make doubtful water safe to drink. The US Environmental Protection Agency advises a rolling boil for at least one minute, and three minutes at high altitude. If water is cloudy, let it settle and pour it through a clean cloth or coffee filter first. When a boil-water notice is issued, follow its instructions exactly; Dutch water companies, for example, ask people to boil for three minutes.

If you cannot boil, unscented household bleach works: the EPA’s table gives 2 drops of 6% bleach per litre (8 drops per US gallon), stir, and wait 30 minutes. Double the dose for cloudy or very cold water. Tablets and filters are lighter and simpler; we compare them in water purification tablets vs filters.

Treated water is not automatically safe after a flood or chemical spill. If authorities say tap or surface water is contaminated with chemicals or fuel, do not drink it even after boiling.

A simple water plan

Buy six 1.5 L bottles per person this week. That is your 72-hour minimum done.
Add one collapsible container for collecting water from distribution points.
Keep a pack of water purification tablets in the kit as a backup.
Put a reminder in your calendar twice a year to check dates and refresh home-filled water.

Then work through the rest of the 72-hour checklist, starting with food that needs no cooking.

Questions people ask

How much water do I need for 72 hours?

At least 9 litres (2.4 US gal) per person: 3 litres (0.8 US gal) a day for drinking and basic food preparation. Add more for washing, hot weather, babies and pets.

How much water does a family of four need for three days?

At least 36 litres (9.5 US gal). If you want enough for basic washing and cooking too, plan closer to 100–120 litres (26–32 US gal).

Can I store tap water for emergencies?

Yes, where your tap water is safe to drink. Fill clean, food-grade bottles or jerrycans with cold tap water, close them tightly, write the date on them, keep them cool and dark, and replace the water every six months.

How long does bottled water last?

Sealed bottled water is safe until its best-before date if you store it out of sunlight and away from heat and chemicals. Rotate it by drinking the oldest bottles first.

Is water from the toilet cistern drinkable?

Not without treatment, and never the bowl. Use cistern water for flushing and cleaning. For drinking, use stored water, the hot water tank or water from pipes, and treat anything doubtful.