How to Store Water in Your Car for Emergencies

Storing water in your vehicle is a great idea no matter where you live. After all, chances are you keep some other survival supplies in there, including a get home bag if you are like me, and when you consider the amount of time that the average adult spends in their vehicle having a stash of survival supplies in there makes good sense.

Water is certainly high on that list of most important survival provisions.

But mistakes get made when preppers store water in their vehicles with nary a thought. Water in bottles, water in bladders and water in jugs and canisters can often fall prey to extreme temperatures or just the rigors of being tossed about in working vehicles.

Just like any other facet of prepping, the devil is in the details.

In today’s article, I’ll be giving you a primer on keeping water and your vehicle for emergencies: why you should, how much, how to store it and pitfalls to avoid.

I’ve got the keys, you grab the water! Let’s go!

Reasons to Keep Water in Your Vehicle

There are several compelling reasons to keep water in your vehicle. The most obvious is for drinking in case you get stranded somewhere along the road, or at a destination with compromised water supplies.

Dehydration is a major killer in survival situations, and you’ll be seriously debilitated long before you die from it, which will hamper your ongoing efforts to survive.

Don’t forget that you may not be the person who needs the water; you never know who needs a drink. You can be the Good Samaritan if you have that clean drinking water on hand.

Clean, purified water is also valuable for various medical emergencies. Irrigating wounds, flushing eyes and cooling burns are just a handful of first aid uses for bottled water.

Yes, distilled water is best for all of those things, but clean, unopened bottled water is the next best thing. I promise you that either will beat what you can get out of a tap or out of a puddle or pond.

Lastly, if your radiator starts leaking, you can use water in an emergency or a mixture of water and coolant to top it off and hopefully limp your car safely to a place where you can repair it or you can find service.

The Effects of Temperature on Vehicle-Kept Water

There are a couple of things you should keep in mind when keeping water in your vehicle, especially if you live in a cold climate, or are preparing for a cold winter.

Water freezes. Duh, I know. Water also expands when it freezes, which means it will bust containers that it is kept in if it has no more room to expand within.

This will obviously be a pain in the butt when it eventually thaws and soaks the daylights out of your car’s interior or trunk but the bigger issue is that you will be out the water that might save your life if that occurs without your knowledge.

A container of water that has some room in it for the water to expand may freeze but it will still be intact and safely contained within.

What about keeping water in very hot climates? This is a worry that seems to be on the minds of a few preppers, mostly having something to do with plastic leaching chemicals into the water when they get hot and so forth.

As best I can tell, even grocery store bottled water bottles will not leach harmful chemicals into the water within when they get hot, or at least they won’t do it in any significant quantity that will hurt you.

I’m making no declarations about long-term intake of any potential chemical contaminants in this situation, but a toasty hot, sealed bottle of water you pull out of your trunk in the middle of August is safe to drink, if unpalatable.

There are three main ways to store water in your vehicle: in the cabin, in the trunk and on external racks in cans for the purpose.

Each of these methods has merit, but only vehicles specially equipped with external racks can make use of the latter method.

Trunk Storage

Keeping your water in the trunk along with the rest of your typical survival kit is a popular way to store it.

The average trunk space in a sedan or SUV is more than ample for a vehicle recovery kit, survival kit and a small case of water with plenty of room left over for groceries and whatever else you want to toss back there.

Keeping your water here also reduces the likelihood that it will be turned into a missile if you get into a high-speed collision. While the idea of flying water bottles in a collision might seem whimsical, the density of water held in a container makes it very dangerous.

If you do decide to keep your water in the trunk, you have a couple things you need to keep in mind.

First, make sure the water is secured with a cargo net, bungee, or tie down straps so it doesn’t skid around and potentially get punctured or break its seals.

Second, consider that the trunk will heat up or get cold much faster than the insulated cabin of the vehicle.

In areas that are very hot or very cold, this won’t make much difference at all, but in more temperate zones the difference of only a few degrees can mean the difference between frozen water or chilly water that is ready to drink straight away.

Cabin Storage

The cabin or passenger compartment is the other default place for storing water inside your vehicle. This works fine with a few caveats. Obviously, storing anything but a few bottles of water inside the cabin area of most vehicles will gobble up space for passengers.

Additionally, and of more concern as mentioned above, anything that is not secured inside the cabin of the vehicle during a collision can become a dangerous missile injuring the people within.

A heavy jug or case of water that is launched at speed has a significant amount of momentum, more than enough to inflict serious injuries on whoever it hits.

One should also keep in mind when stashing water within the vehicle to pay attention where you put it. It is an easy thing to accidentally close the door on a case or jug of water, rupturing it.

Some people like to store single bottles of water under their seats to keep them out of direct sunlight, and also out of the way. These people invariably learn the error of their ways as soon as someone adjusts the seat, crushing the bottles beneath.

There is one perk of keeping water in the cabin of the vehicle though, and that is it benefits from better insulation.

This is of most interest to those people who live in cold climates, since water kept in the cabin will not reach freezing temperature as quickly as water kept externally or in the trunk of the vehicle.

You can keep water inside the cabin of the vehicle, and there are times when you should definitely move the water from the trunk to the cabin, but overall you’re better off keeping water in the trunk.

External Storage

For vehicles equipped with external storage racks or specialty can holders, you can keep large quantities of water outside of the vehicle, freeing up room in the trunk and the cabin for passengers or other things.

If you were simply worried about moving as much cargo as possible or carrying great quantities of water, this is the ideal solution.

Your choices are simple: You can take jugs or cases of water and strap them down to external cargo racks using nets or tie down straps as with any other carried cargo or you can mount special water cans to their holders.

The former is easy and requires the least amount of modification to your vehicle but keep in mind this is a bit of a touchy procedure as water bottles are flexible and compressible to a degree, and on long trips they are very likely to vibrate loose if care is not taken to secure them.

A more specialized method for external storage of water on your vehicle is the utilization of cans for the purpose. Water carrying cans often look just like the classic gasoline Jerry cans of old, only they are specially lined and intended only for water, nothing else.

I shouldn’t have to mention this but don’t ever dream of using a can that previously held gasoline or other fuels for the carrying of water. Just don’t do it…

At any rate, these cans will fit on specialized holders or racks designed to securely and safely carry them over the most rugged terrain with no damage and minimal risk of losing it. Other alternate options for SUVs and some trucks are spare tire mounted water containers.

These specialty containers usually mount behind or in front of the spare tire on the tailgate and will carry several gallons of water securely and in a way that save space inside and outside the vehicle for additional cargo.

The obvious major drawbacks to carrying water outside the vehicle are increased vulnerability to both theft, and to the elements.

Anything outside your vehicle will become hotter or colder faster, and especially will freeze quickly if carried externally while driving in cold conditions; wind strips heat, y’all.

Regarding theft, if people can see it, and your vehicle is unprotected there’s always a chance that someone will try to steal it.

Perhaps not an issue if you are overlanding or bugging out since you will be staying with the vehicle, but you need not think you can keep externally stored water on your vehicle while you go about your business in public without it disappearing one day.

Internal Storage – Containers

You have a few choices for carrying drinking water inside your vehicle internally. Much of this will boil down to preference, but each method has advantages and disadvantages you should be aware of before going with one over the other.

Bottled Water, Multipack

A case of bottled water is not as space efficient as a larger container, meaning it will take up more room to carry the same amount of water as a larger single cell.

That being said, redundancy does count for something and you can open a bottle at a time without breaching the seal on the rest of your supply, meaning it will stay safe and germ-free.

Additionally, losing a bottle or three does not mean you have lost the entire water supply, or your ability to carry the water. For vehicles that have room to spare, this is probably the best option.

Bottled Water, Jugs

The larger liter, 2-liter and gallon jugs of drinking water you can buy are more efficient when it comes to space, but also come with more vulnerabilities and are harder to carry than their multipack cousins.

If you need to take off on foot with the water you will be hauling a container that will weigh several pounds, perhaps over ten. If something happens to that bottle, it starts to leak, or gets broken your water supply is now compromised and also vulnerable to loss.

You could ditch a single cracked water bottle from a case and be okay. If your vehicle is smaller or you are really trying to pack in as much as you can, these larger jugs are the way to go.

Refillable Containers

Refillable containers come in all shapes and sizes, from the ubiquitous Nalgene liter bottle to 5-gallon, flat and stackable rectangles.

These containers are multi-purpose, refillable, reusable and allow you to reseal the water after drawing what you need and are far more durable than disposable bottled water containers.

There is just one problem though: No matter how thoroughly you clean and sanitize these containers, and no matter how pure the water is that you put in them, the water will always start to go a little funky in these containers, where factory bottled water will not or at least do so far slower.

It is possible to get longer life out of the water by adding some stabilizers, or by very cautiously and carefully adding a prescribed amount of unscented bleach, but that is just the price you’re going to pay for having a more durable container that is reusable.

If you decide to make a reusable container you fill yourself for your long-term water storage solution for your vehicle, you’re going to have to be dedicated to refilling it with fresh water periodically and staying on top of it.

Maybe that layer of algae scum that forms on your water after leaving it in your trunk for the summer isn’t harmful, or maybe it is. At any rate, it is unbelievable and good luck getting anyone in your family to drink it.

A Thought About Filtration

It seems to me that most preppers don’t keep a portable emergency water filter with their vehicle survival kit since the water contained therein is factory purified and sealed or is loaded into their own (hopefully) sterile containers.

This reasoning is generally sound, but may be an unnecessary risk.

As clean as bottled water is, there is a non-zero chance that water left for a long time may experience a bloom of bacteria, or of other microorganisms. This is of significant concern if you fill your own portable containers of water.

If you are worried about such an eventuality, don’t neglect to carry a portable water filter with your kit.

Good examples of these devices will allow you to filter out any algae and microorganisms are the Lifestraw and the Sawyer Mini. Plus, keeping a water filter handy is just good sense, no matter what the situation is!

Keeping Your Water from Freezing

Water kept in your vehicle freezing is a much worse outcome than it getting hot, for all the reasons we went over above. Therefore, you should take precautions to ensure that it does not freeze.

First, know the weather and the climate where you are. There will be some seasons you won’t have to worry about this at all. Some of you have to worry about it every single day, year-round.

I leave it up to you to know the risks, and know how far you can push it before you need to worry about your water freezing in your vehicle.

Below are a few methods you can rely on to keep your water in a liquid state, or to at least keep it liquid longer, when the vehicle is not running. You should definitely combine one or all of these methods to keep your water as liquid as long as possible.

Method #1 – Wrap It

Wrapping your water, no matter what container it is in, in thick blankets or even something like an emergency survival blanket insulates it and helps keep it liquid longer. The more you can wrap it, the longer it will stay liquid.

Just one caution though: your container had better be very durable and have very good seals if you’re going to use your emergency blanket, the one that you would use for warmth.

If your water leaks or the container gets broken, you will have a soggy, useless blanket to deal with in addition.

Method #2 – Cooler

Cooler? What?! I thought we were trying to keep the water from getting cold? We are, settle down now. A cooler is just an insulated container. They only keep things cold if their internal temperature is cold.

Anything that is put into a cooler at ambient temperature will resist plunging temperatures more than leaving it sitting around exposed to those temperatures.

You can stick your water supply in any insulated container you desire from any manufacturer you wish so long as it fits, and your water will dependably remain liquid significantly longer than it would if it was just sitting in the trunk or in the cabin.

Obviously this method will gobble up even more space and, depending on how much water you are storing, you may need a very large cooler indeed, so this works best for smaller containers of water.

Method #3 – Keep it in the Cabin

As mentioned throughout this article, your water will benefit from the better insulation of your vehicle’s cabin compared to the trunk and obviously external storage.

Depending on the climate and the season, you might be better off moving water from the trunk to the cabin for the duration of the lowest temperatures to buy yourself time.

Additionally, if you know you are facing an oncoming temperature plunge, you can preemptively move the water from the trunk into the cabin until temperatures normalize.

Thawing Frozen Water

For those of us who live in extremely cold climates or are dealing with sharp and brutal winters, frozen water is just going to be a fact of life. No matter what you are doing, no matter how much you try to prepare, chances are good that your vehicular water supply will freeze at some point.

There’s no need to freak out over this, and if you are a good prepper you’ll be prepared for this eventuality with several methods to thaw it out.

Some of these methods work quicker than others, so choose depending on how quickly you need to access liquid water.

Option #1 – Run the Heater

If you are stuck with your vehicle and it still runs, all you need to do is run the heater periodically, and keep the water in the cabin near the floorboard vents. It will thaw in no time.

Option #2 – Use Hand/Foot Warmers

I keep hand and foot warmers in my vehicle survival kit in the winter time specifically for this purpose. If you have a frozen bottle of water, crack one of your hand warmers, place it next to the bottle and then wrap it up. This will thaw it post haste.

Option #3 – Stove

If you need water right away, and you have a stove and fuel among your vehicle survival kit contents or in your GHB, you can cut open the container (if possible), and add the chunks of ice to a small pot or cup that will withstand the heat and flame of the stove.

Crank that sucker up, and you’ll have that ice melted in seconds. An alternate option is to set up a simple improvised stove with a metal container and use something like a road flare to heat the vessel and melt the ice. Make sure you do any of the above outside your vehicle!


Keeping a supply of drinking water inside your vehicle as part of your vehicular survival kit is a great idea. There are all kinds of situations you might need clean water on demand, and not just for drinking.

Knowing the best way to keep water in your vehicle while protecting it from heat extremes and your containers from damage is the biggest part of keeping water in your vehicle intelligently. Use this article as your guide and toss a few gallons in there so you’ll be ready on the road!

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