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How to Store Emergency Water in Your Car Year Round


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Last Updated: May 17, 2021

One of the essential car emergency supplies is water, but storing water in your car isn’t that simple. It has to withstand temperature extremes. There are also issues like accessibility to consider.

In this article, I’ll go over everything you need to know about storing emergency water in your car:

Storing water in your car the key takeaways:

  • Keep canisters of water and a funnel in the trunk of your car.
  • Put the canisters inside a cooler to protect against temperature extremes, bad smells, and leaks.
  • Also, keep a few high-quality bottles of water inside your car.
  • Rotate your supplies every 3-6 months.

Choosing the Right Water Container for Car Storage

The first thing you want to decide is which containers to use for storing water in your car.  Some containers are better able to handle extreme temperatures, but they tend to be pricier.

I have several mid-sized canisters of water in the trunk and a few insulated flasks of water inside the cabin.

Let’s briefly go over the options and their pros and cons:

Bottled Water

  • Cheap
  • Convenient

  • Eventually leak
  • Absorb bad smells
  • Chemicals leaching into water

Plastic Water Canisters

  • Don’t degrade/leak
  • Durable
  • Easy to store large amounts of water

  • Difficult to pour
  • Absorb bad smells
  • Inconvenient to use
  • Hard to defrost

Glass Jars

  • Don’t absorb bad smells
  • No plastic chemicals

  • Break easily
  • Difficult to pour
  • Heavy
  • Hard to defrost

Bagged Water

  • Convenient package size
  • Don’t degrade/leak
  • Long shelf life
  • Easy to store
  • Withstand extreme temperatures

  • Expensive

Stainless Steel

  • Don’t degrade/leak
  • Durable
  • Insulated options

  • Expensive

Canned Water

  • Good for hot temperatures
  • Convenient packaging

  • Burst in freezing temperatures

1. Bottled Water (or Recycled Plastic Bottles)

can you put water bottles in the car

Yes, it is safe to put plastic bottles of water in your car. So long as you don’t overfill them, plastic bottles can even withstand freezing well.

However, you will need to rotate the water every 3-6 months. At least once per year, you’ll have to completely get rid of the bottles along with the water, which means a lot of plastic waste.

Leaking

Water never goes bad. However, the bottles that contain water are designed to be biodegradable.  Over time, tiny holes will form in the bottles.  You might open your trunk to find water has leaked all over.

Heat and UV light speed up the plastic degradation process, so plastic bottles might only last 3 months in your car in summer before they start to leak.  Thicker plastic bottles (like Fiji water or Gatorade bottles) will last much longer than the thin cheap bottles which come in value packs.

Bad Smells and Tastes

Plastic water bottles, especially those made of HDPE, are permeable to gas.  If you leave the water container sitting in your car long enough, the water will start to taste musty and gross.

In an actual emergency situation, you won’t care if your water tastes nasty.  However, if you want to use the water in your car during non-emergency situations, you’ll have to rotate through it quickly, so it doesn’t taste nasty.

Plastic Chemicals Leaching into Water

Whether or not chemicals from plastic bottles really leach into water, there’s no doubt that water starts to taste like plastic when it’s sat in a bottle for a long time, especially in high temperatures.

Bear in mind that BPA isn’t the only chemical used to make plastics, so even BPA-free containers could leach chemicals.

Read more about food-safe plastics.

In a true SHTF situation, you probably won’t care whether your emergency water contains some chemicals.  The real-life risk of dying from dehydration outweighs the risk of ingesting some chemicals.

However, if you plan on regularly using the water in your car stockpile, you might want to choose containers that don’t leach chemicals.


2. Plastic Water Containers and Canisters

Ready Store water storage container

Unlike the cheap plastic used to make bottled water, plastic water canisters are meant to last a lifetime. You won’t have to worry about leaks from holes forming in the plastic.  The plastic is still porous, so the water will eventually start to taste and smell bad.  However, you can just rotate the water and won’t have to get new containers each time.

One of the main downsides of water containers is that they are large.  It is tough to pour water so you can drink it (tip: choose a container with a spigot or put a funnel in your car!).

They are too bulky to take with you if you need to leave your vehicle.

If frozen, they will be virtually impossible to defrost. And you won’t be able to share/trade water like you could with small bottles of water. However, this is still the easiest, affordable way to store a lot of water in your car.

For smaller amounts of water, I like the Nalgene Oasis.

For larger amounts of water, I like the WaterBrick and Scepter military can.

See this post for my other picks for the best water storage containers.


3. Glass Containers

glass carboy for car water storage

I generally don’t like to put any of my emergency supplies in glass containers; the risk of them breaking is too high.  Like canisters, they are also tricky to defrost.

However, many preppers use glass water containers like carboys in their vehicles.  Glass isn’t porous, so the water won’t absorb bad smells.  There also isn’t an issue with plastic chemicals potentially leaching into the water.

If you go with glass containers, make sure they are completely wrapped in a sheet or something similar. Then, if there’s an accident and the container breaks, you can just toss the entire sheet.

4. Bagged Emergency Water

bagged emergency water

While bagged water admittedly does seem overpriced, it is worth considering for your car.

Bagged water is designed to withstand extreme temperature fluctuations. They come in small pouches, so they are easy to carry.

The flexible packaging also makes them easy to store in your car, such as in the inside of your spare tire.  Even if one pouch breaks, it won’t cause much of a mess. And because the packaging material is thicker, it won’t absorb bad smells as quickly.

Make sure you only choose bagged water which is approved by the United States Coast Guard.  See the best brands of bagged emergency water here.

5. Stainless Steel Water Containers

stainless steel water bottle for car storage

Stainless steel bottles are great for storing water in the car.  They won’t degrade, so there’s no worry about holes forming like with plastic bottles. Stainless steel also won’t let bad smells get through, so the water still tastes good even after sitting around for a long time.

There are also lots of vacuum-sealed stainless steel water bottles which will keep water from freezing as quickly.

The problem is that stainless steel water containers are pricey.

There are cheap ones, but the lids might leak or be impossible to open if frozen.

For this reason, I recommend getting a few good vacuum stainless steel bottles and keeping them inside your car.  Because they are inside your vehicle, the water probably won’t freeze even in cold weather.  You can always refill the bottles from your canisters.

I like this vacuum-insulated water bottle, and it comes in sizes up to 64oz.

Note: Single-wall stainless steel canteens can go directly on flames. But never put an insulated or double-walled stainless steel container on flame – it can explode!

6. Canned Water


In hot climates, canned water is a good alternative to plastic water containers. Canned water withstands very high temperatures without degrading.

Yes, the water does have a slightly metallic taste, but you won’t get a nasty chemical taste after just a few days in the heat (as is the case with plastic bottles).

However, canned water is not suitable for cold climates because the cans will burst if frozen.

Blue Can is well-reviewed and has a 50-year shelf life.

Storing Water in Your Car during Cold Weather

The biggest problem with storing water in your car in cold weather is that it can freeze.  Not only can this cause leaks, but it can make the water unusable.

You’ll want to keep water in your trunk in a cooler, keep insulated bottles inside your car and have a way to melt frozen water safely in emergencies.

Preventing Leaks

Water expands by 9% when frozen.  Leave at least 10% space in the water container to allow for expansion. Store-bought plastic water bottles generally handle freezing very well.

They have headspace in the bottle, and the plastic is flexible enough to handle distortion from the frozen water.

As a safeguard, you might want to keep the water in a cooler: if the bottles do leak, the cooler will prevent a mess.

Keeping Water From Freezing in Your Car

Ideally, you should always have at least a small amount of unfrozen water in your car. This will give you water to drink immediately and also act as a “starter” for melting any frozen water (see below).

To prevent your emergency water from freezing:

  • Bring a bottle of water with you when you leave: Get in the habit of taking a bottle of water from home when you leave so you’ll always have at least one which isn’t frozen.
  • Keep water inside the car: Water left inside the car cabin (as opposed to the trunk) generally won’t freeze as quickly because your car periodically is warmed up.
  • Insulate containers: I keep vacuum-insulated stainless steel bottles of water inside the car and have never had them freeze completely. The water in the trunk goes in a cheap cooler.
  • Choose larger canisters: Large canisters of water take longer to freeze than small bottles. However, the tradeoff is that the large canisters are harder to defrost.
  • Stockpile electrolyte or sugar drinks instead: Electrolytes (like in Pedialyte) and sugar will reduce water’s freezing temperature. For example, Gatorade freezes at approximately 18F.

Melting Frozen Water in Your Car

In very cold climates, there’s almost no way to avoid water freezing in your car.  You’ll need a way to warm it up so you can use it.   Ideally, you can melt the vehicle while still inside your car, so you don’t have to get cold going outdoors.

Some options for melting frozen water are:

  • Camping stove and pot
  • Candle stove-heaters
  • Handwarmer packets
  • Put container on engine hood while it is still warm (without melting the container, though!)

Note: Ice and snow melt faster when there is a bit of water at the bottom of the pot to act as a “starter,” otherwise, the pot will scorch before the ice/snow had time to melt.

Warnings:

  • Do NOT eat ice or hold containers against your body to melt the water inside. This will lower your body’s core temperature, possibly killing you.
  • To prevent CO poisoning, always leave a window cracked when using stoves in closed spaces.
  • Use common sense when lighting a flame inside a car!

Storing Water in Your Car in Hot Temperatures

When it is 100 degrees F outside, it can quickly get to over 170F in your vehicle.

At this temperature, plastic bottles quickly start to degrade.  In just a few days, the water will already have a gross plastic taste to it. A lot of people worry about the plastic chemicals leaching into the water.  The heat will eventually damage the bottle enough for holes and leaks to form.

For these reasons, don’t put cheap plastic water bottles in your car in hot temperatures!  If you must, then at least put them in an insulated cooler.  The cooler protects against the heat and will catch any water which leaks.

Quality water canisters withstand heat much better.  However, the water will still start to taste bad after just a few days. Putting them in a cooler will help reduce bad tastes, but not completely.

If you don’t want your emergency water to taste gross, your only options are to invest in some quality glass or stainless steel containers. Cans of water also withstand the heat well but have a metallic taste.

Where to Keep Emergency Water in the Car

You’ll want to have a supply of emergency water inside your car, so it is easily accessible and also some in the trunk.  Here are some ideas and considerations for where to put the water in your vehicle:

  • Inside spare tire: Bagged water packets fit in here very well. The water is concealed here too.
  • Under the seat: Just be warned that lots of new cars have sensitive electronics under the seat. Check first and make sure the container has a reliable seal.
  • Trunk organizers: These make it a lot easier to keep all of your car emergency gear organized.
  • Glove box: Again, ensure that the water bottle is reliable so it doesn’t leak on essential documents.

Rotating Car Emergency Water

As a general rule, you’ll need to rotate water every 6 months.  Water stored in quality containers can go longer without rotating.  It will taste bad but should still be safe to drink for a year or more.  When rotating, you can use the water for watering plants or flushing toilets.

If you store water in cheap plastic bottles, you’ll need to rotate more frequently: once every 3-6 months. When you rotate, you’ll need to get rid of the water AND the bottle. Otherwise, leaks may form in the bottle.

Extra Tips for Storing Emergency Water in Your Car

Put Your Water in a Cooler

The cooler will protect against temperature extremes and leaks.  It also reduces the amount of bad odors the water will absorb from the car.

Keep Water Away from Car Fluids

The water will absorb odors from gasoline, antifreeze, coolants, and other fluids you might have in your trunk.  Keep them stored away from each other, or at least put the water supply in a cooler or other food-safe container as a layer of protection.

Stock Small and Large Containers

Small containers are much easier to use and can be traded/given away.  You also won’t lose all of your water if a leak occurs. But larger containers make it easy to store and rotate large amounts of water. To get the benefits of both small and large containers, diversify the size of your containers. I’ve got a few mid-sized canisters in the trunk and many small bottles inside the car.

Pack a Funnel

A funnel makes it much easier to pour water out of bigger containers into bottles or pots.  You can also get canisters with spigots.  Just make sure that the spigot and cap are located on the same side: then you can store them upwards, so you don’t have to worry about leaks.

Keep a Map of Water Sources

This will help you find water if your car supply runs out.  In some Western states like Arizona and Nevada, you can find maps of water catchments that were built for cattle. Ask the local Fish and Game Department if they have any maps.

Have Ways Treat Water

Always have at least two ways to treat or purify water. Then it won’t matter if your car emergency water grew algae.  You’ll also be able to treat water from nearby sources for drinking.

Do you have any other tips about car water storage? Let us know in the comments section below.

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