How Much Water Do You Need to Store for a Level 1 Situation

A store of 3.5 gallon 'brick' water containers.
A store of 3.5 gallon ‘brick’ water containers.

Water is the third of the survival essentials.  Air is first, shelter is second, and food is fourth, and you’re probably familiar with sayings like ‘you can go without air for three minutes, shelter for three hours, water for three days and food for three weeks’.

Actually, we’d not like to have to prove any of those four claims!  But you get the general point that they try to make.

So, having acknowledged the essential need for water, the next question becomes ‘How much water do you need to store?’.  That’s an easy eight word question to ask, but we’re going to take just over 3500 words to answer it, because the first part of the answer is ‘it depends’.

Let’s have a look at some of the dependencies that go into answering this essential question.

How Many Days of Water Do You Need to Store?

The first thing that is a massive dependent variable is how long you believe you will be without water.  Are you planning for a Level 1, 2 or 3 type situation?

If you’re planning for a short-term Level 1 situation – something that you’ll stay at your normal residence for, then probably it is prudent to consider a two-week outage as a sort of reasonable period to have water on hand for.  If you’re still without water by the time two weeks approaches, you’ve probably got other very pressing worries on your mind as well as water (ie probably no utilities and no food and increasing problems with the maintenance of law and order) and you will be needing to consider ‘getting out of Dodge’ for all these reasons.

That’s not to say that having more than a two-week supply of water is a bad thing.  We’re simply suggesting, that for a Level 1 type response, two weeks of water should be the minimum you have.

In a Level 2 situation, you may also choose to prepare for that with stored water, or you may instead ensure that you have some type of ongoing water source/supply (such as a well).  Quite possibly, you’ll have a mix of both.

Pretty much by definition, Level 3 preparations require you to have a viable ongoing supply of water rather than be relying on stored supplies.

However, although both these other types of more severe scenarios have a growing dependence on renewable sources of everything, you should still keep an emergency backup supply of stored water too.  For example, what happens if your well pump fails?  You’ll still need water until such time as the pump is repaired.  What happens if the well runs dry?  You’ll doubly definitely need some stored water while urgently seeking a new ongoing source.

Note that even a Level 1 response can also consider sources of ongoing water as well as relying on stored water.  Maybe you have a rainwater collection system, maybe you have a creek and water purification capability.  But in most parts of the country, there are times of year when no rain will fall for more than two weeks in a row, and if your creek is seasonal, that’s not a guarantee of water either.  So we suggest that you probably should keep at least two weeks of water on hand.

How Much Water is Needed per Day?

The classic rule of thumb is to allow one gallon of water per person for each day of water you are storing.  Now that’s not the same as saying you all need to drink a gallon of water a day, although many people confuse these two points.

The amount of water you need to drink to maintain reasonably good health depends on how much work you are doing, what you are eating, and the temperatures around you.  The more work you do, the more water you need.  Similarly, the hotter it is, the more water you need.  But some – most – of the foods you eat contain water within them and so help you get towards your daily water needs.

One rule of thumb says you should drink eight glasses of water a day, each with 8 oz of water, making a total of 64 oz, 4 pints, 2 quarts, or half a gallon.  This is probably on the high side of normal, and also can be adjusted down for the water you also receive from food (and, ahem, from wine or beer too!).

In addition to drinking water for basic survival, there are other close to essential needs for water.  The most immediate is water for cooking.  Try boiling vegetables without water to boil them in!  Try steaming rice without water to steam.  And so on.  (Actually, there are ‘dry’ steamers that use little or no water to cook vegetables, and also fatless fryers too.)

If you are able to keep the water you’ve used for boiling vegetables chilled, you can store this water and reuse it for several days, and then use it as a soup base.  This is a very good thing to do because you are capturing all the vitamins and minerals and flavors that leach out of the vegetables and into the cooking water.  It improves each batch of vegetables that reuses the same water and makes for wonderful soup at the end, as well as reducing your water consumption, too.

You also have some water needs for basic hygiene.  Try brushing your teeth without water.  Or washing your hands.

Beyond these essentials – drinking water, cooking water, cleaning water, you then start to move towards more ‘luxury’ type water uses.  For example, one of the greatest aspects of modern civilization is surely the flush toilet, and each time you push the flush lever, you are using 1.2 gallons or more of water, depending on your toilet design.  If you still have a working sewer system, how many times a day will you treat yourself to flushing your toilet?

Note that it may be possible to re-use your washing up water for flushing the toilet (ie using your ‘grey’ water).  There are some issues and considerations if you were going to do this long-term, but for short-term needs, it is perfectly fine to fill the toilet cistern with the water you used for washing your hands or dishes or whatever else.

In normal life, a typical American uses an average of between 50 – 100 gallons of water a day for all purposes, possibly also including outdoor/gardening activities as well.

So there’s an enormous gap between our normal lifestyle consumption of 50 – 100 gallons of water a day, and our bare minimum need of – well, of what?  Is the one gallon of water per person per day a useful number of rely upon?

A one gallon per person per day allows for half the gallon for drinking and half the gallon for all other uses.  In a dire emergency, this is sufficient to survive, but clearly, the more you can add, the more comfortable you’ll be.

Doing the Sums

So let’s see what happens now that we are saying we want to store at least one gallon of water per person per day, and at least 14 days of water in total.  If you have three people in your residence, that would be something in excess of a 42 gallon store of water.

Our point, in case it is not obvious, with the ‘at least’ emphasis is that there’s really no such thing as storing too much water, but there definitely might be a problem if you have too little.

How much is 42 gallons?  A couple of easy ways to visualize this is that it is less than a single 55 gallon drum, and it is the same as about seven or eight typical 5.5 – 6 gallon plastic gas ‘cans’.  It is also the same as about 80 2-liter plastic soda containers.

Hopefully you’ll agree this is not a ridiculous or impractical amount of water to store (and based on the calculation above, we’d massively increase the amount we stored, to something more than 100 gallons).  Water weighs 8.34 lbs/gallon, so 42 gallons has a total weight of 350 lbs – you’re not going to have any floor loading problems.  And you can already visualize the very limited amount of space you’ll need (there are 7.48 gallons of water per cubic foot so in total there is 5.6 cu ft of space required – think of a cube with each side measuring 20″ and that’s how much space 42 gallons needs, if stored in the most efficient manner possible).

Which of course then begs the question – if you can easily store one gallon of water per person per day and keep 14 days worth of water on hand, why not store more than this?  That’s a great question, and we’re delighted you’re asking it!  Yes, absolutely, you should keep very much more than this so as to be able to treat yourself to a more comfortable lifestyle during the water outage, and/or so as to have additional essential water supplies if you are sheltering other people, or have unexpected water needs, or need to survive for more than 14 days.  Water is cheap and easily stored.  You’ve no conceivable excuse for not having a lot on hand.

And more water – some ‘spare’ water – would also to allow you to occasionally flush a toilet!  Make sure at least one of your toilets is a modern very low water consumption per flush type – it seems that currently you can find them using as little as 1.2 or 1.3 gallons per flush.

What to Store Water In?

recycleThe two best types of storage containers for water are stainless steel and glass.  These are the most impervious, longest lasting, least reactive and easiest to clean.

The other obvious alternative is some type of plastic container – either a container you’ve purpose-purchased specially for water storage or one you’ve repurposed from some prior use.  Plastic is ideal for portable water storage, because it is less breakable than glass and lighter than both steel and glass, and is more likely to be shaped into suitable sizes for storing and carrying.

If you are using plastic, you want to limit yourself to food-grade plastic that won’t leach out any of the moderately poisonous chemicals that are often used in the manufacture of plastic containers, and which aren’t made of poisonous plastic to start with.

The recycling number shown on the side of most plastic containers (and illustrated here) allows you to understand if it is suitable for storing food and water or not.  If it is type 1, 2, 4 or 5, then it is made of a suitable type of plastic.  Some types of #7 plastics might also be okay, but you probably have no way of knowing if it is a suitable or unsuitable type 7 plastic, so best to leave well alone.

This page tells you more about each type of plastic.

Note also that plastic is somewhat permeable and allows gases to migrate through itself.  Water can’t leak out, of course, but smells can leak in.

That means that if you are storing your water in an area with strong smells or other gaseous products, the water will gradually acquire those smells through the plastic.  Glass and steel are, for all intents and purposes, totally impermeable.

Because of the permeability of plastic, when we are reusing plastic containers, our preferred choice is to use soda type plastic bottles that originally held some sort of carbonated beverage, because these types of plastic containers have lower permeability (so that the soda or sparkling mineral water inside doesn’t lose its fizz).  The least desirable are the small size plastic bottles that hold regular water.  These are so thin these days that they offer very little gaseous barrier.

If you are re-using a container, you want to be sure that it is thoroughly clean prior to adding water to it.  Some things are easier to clean than others, and according to this page, milk jugs are surprisingly difficult to clean.

The chances are that you’ll be storing your water not in the same place that you’ll want to use the water, so we’d be tempted to keep the water in carry-sized containers – ie, probably less than ten gallons per container.  Otherwise, if you have a more ‘industrial grade’ bulk tank of water, you’d simply want a tap (or a siphon or a hand-operated pump) that you can use to then fill transfer type containers to take the water from where it is stored to where you’ll be using it.

We obviously suggest hand rather than electrical operation of a water pump because electricity might not be available, and to keep the pump’s operation as simple and trouble-free as possible.

Note that if you’re using a hand-operated siphon/pump, that too needs to be food grade.

There is an obscured issue with large-sized water storage containers.  As you’ll see below, we recommend replacing the water every year or so.  This is relatively easy to do when you just need to carry the containers to the sink, pour out the old water, and run new water in from the tap.  It is harder to do when you have to drain in place a large container of water, then refill it also in place.  That’s a lot of water transferring.

Needless to say, Amazon has a wide variety of water storage containers of varying shapes and sizes and costs.  Even if you don’t buy from Amazon, it is a useful reference to start from and gives you a great range of idea generators and a feeling for costs.

When looking at cost, we consider both the utility/good sense of the container and also what the cost works out in terms of dollars per gallon of water stored within the container.

We do like the stackable 3.5 gallon water bricks (see image at the top of this article), even though they are fairly expensive in terms of dollars per gallon of water stored.  They are easily carried, emptied, filled, stacked, and moved about and generally ‘managed’.  They are an efficient size and shape that allows you to make best use of the storage space available.

Their ease of use encourages people to actually do what they should be doing and rotate their water supplies, disposing of the oldest and refilling with fresh water (see the next point below).  Even the children in our group can usually carry one of these at a time, and most adults have no problem carrying two.

Note that most water containers should not be stacked on top of each other unless specifically designed to handle the weight of the extra containers on top.

There are also some excellent 7 gallon water containers that we like as well.  When full, these weigh just under 60 lbs.  Some people can carry two of these, others prefer to carry one at a time.

Anything heavier than this is not really portable and becomes too hard to pour small measured amounts from, and instead becomes more ‘fixed in place’ storage that you then transfer water to and from.

Containers should have lids or in some other way be sealed, and should be filled with water to as close to the top as possible.  This not only keeps out obvious sources of contamination, but it also stops oxygen from getting into the water and possibly feeding any micro-organisms present.

Some people have wondered about storing water in old-fashioned type wooden barrels.  These are acceptable for very short-term storage of water, but not for longer term storage.  Sure, wine and whisky is stored in wooden barrels, sometimes for years, but you don’t then drink half a gallon of wine/whisky every day, and cook with it too.

There are not only flavor-imparting and flavor-modifying chemicals in wood that react to the wine/whisky, but there are also poisons in the wood.  They’re not too poisonous when enjoying the occasional sip of bourbon or glass of wine, but not only would they flavor your drinking water, they’d eventually start to cause some undesirable heath issues too.

The Optimum Storage Environment for Water

Water should be kept in a cool dark environment, and the containers should be filled and sealed prior to storage.

The colder the water is, the better, and if you can freeze it, that is even better still.

Note that if you are freezing water, the water will expand 9% when it freezes, so make sure you have some headspace for this within the container and the cap on loosely, or else it may burst.

Talking about freezing water, we recommend filling up your freezer(s) with containers of water to use up any available spare space.  This does two things.  It gives you more water, and it also gives you a ‘battery bank’ – a thermal reservoir – of cold so that if the power fails in your freezer, it will take longer for the cold to leak out of the freezer and for the food in it to spoil.

The reason to keep water both cold and dark is because even the purest water probably has some micro-organisms in it, and over time, these will tend to grow and make your water taste bad and possibly even be harmful.  These organisms need warmth, light and oxygen to grow.  There’s probably enough dissolved oxygen in the water to allow them to grow to a certain extent, so your best way to slow down their growth is to keep the water as cold as possible and as dark as possible.

How Long Can You Store Water For?

This might at first seem like a ridiculous question.  We know that food has a finite storage life, but water?  What can age in water?

The answer to this question is that the water itself will remain stable and not change.  The concern instead is with the various micro-organisms that might be found within the water.

The best type of water to store is of course water that has as low a contamination level to start with as possible.  Where do you get that from?  The answer might surprise you.

Most of the time, the water direct from the tap in your kitchen is a better choice than any sort of special ‘triple distilled’ ‘ion exchanged’ or whatever else water you might buy from a supermarket or water supply service or anywhere else.

Not only is most city water purified to a very high standard to start with, but it is almost always also chlorinated, which acts as an inhibitor to slow down the future growth of things inside your stored water.  Some people add a splash more chlorine (ie bleach, or iodine instead of chlorine) to the water they store to extend its life still further.

This type of water, optimally stored as we suggested above, will be good for a year or more.  You’ll pretty much know, when you open it, if it remains good or not.  If it looks clean, smells clean, and – yes, tastes clean (by all means have a test sip) then it is clean.

If it isn’t, well, at least you have slightly impure water, which you can variously use for secondary purposes and also which you can then filter or boil (actually, you don’t need to boil water to make it safe, but an easy rule of thumb is that by the time you’ve brought water to the boil, you’ve probably killed off anything within it during the heating time up to boiling) to use for drinking purposes too.

Fortunately, water is cheap, so apart from the hassle factor, there’s no reason not to turn your water over every year or so.  What we do, to try and control the hassle factor some, is we recycle some of it every month, meaning that at any time, we have water of different ages from nearly brand new to about a year old.  Of course, if we ever had to start using it, we’d start from the oldest first, although being as how there is only a few weeks of supply, it probably doesn’t matter too much what order you then drink it!

Obviously, the cooler and darker the water, the purer it was to start, and the more airtight the container, the longer it will last.  The opposite is of course also true – if you’re storing water in ambient temperatures in the 80s or 90s, then it will need replacing very quickly – definitely at the end of every summer and maybe partway through the summer, too.

A Tip for When You are Filling Containers With Water

When you fill a container with water that you intend to store for the next year or whatever, try to pour the water into the container ‘smoothly’ without introducing a lot of air.  Think of filling a beer growler, perhaps, as an example of how to do this.

You should ideally have a plastic hose that runs from the tap to the bottom of the container.  Turn the water on slowly, and only increase the flow rate as the bottom of the container is covered, and make sure there is no bubbling or undue agitation of the water while the container fills.  Don’t shake it after you’ve filled it, although if you do find air bubbles on the sides of the container, definitely tap the sides to dislodge them.

If you’re filling straight from the tap, have the water run down the side of the container.  Again, think of the water as if it were beer, and your objective is to avoid the ‘beer’ foaming and getting a big head as a result of your pour.

Level 2 & 3 Storage Requirements and Considerations

This article is primarily focused on how much water you need to store to get you through a short-term disruption to your water supply.  As per the definition of a Level 1 situation, this is a short-term problem where you can realistically foresee a relatively fast and certain restoration of normal service, and in such cases, a fairly limited store of water is all you need.

If a scenario lengthens and becomes more a Level 2 or worse situation, then your issues and your preparing changes.  Your focus becomes on bulk water storage and ongoing water resupply strategies.  We suggestion you read through our other articles on water for further ideas and suggestions.

Note we also suggest you keep a supply of water stored, even as part of your Level 2/3 preparation.  So that probably means stored water both at your normal residence and at your retreat.


How much water do you need to see everyone in your normal residence through a Level 1 event?  Do you have that much water, and hopefully a bit more too, stored and not too stale?

If you don’t have sufficient water, we urge you to start adding to your water supplies right now.  Even if you do nothing more than clean out 2L soda bottles and fill them with water as you occasionally may buy and consume such things, that is at least making progress (and at close to zero cost) towards having sufficient water for Level 1 problems.

Ideally, we recommend you keep your water in 3.5 – 7 gallon sized containers, because they are easiest to manage – easiest to fill, to store, to rotate, to empty/refill, and to work from if you ever need to use them in a water-down scenario.

Leave a Reply

Your email address will not be published. Required fields are marked *