How to Keep Emergency Water Stored Outdoors from Freezing

Keeping Outdoor Emergency Water from Freezing Title

Water is essential to sustain life, so keeping your outdoor emergency water from freezing should be a priority on your prepping to-do list. Indoor emergency water storage is preferred, but that’s not always an option. Below, I’ll discuss some of the complications that come with storing water outdoors in winter and how you can keep emergency water from freezing.

Keeping Outdoor Emergency Water from Freezing

Why You Don’t Want Your Emergency Water to Freeze

It doesn’t take a rocket scientist to understand that frozen water in an emergency is bad news. The problem goes beyond the minor inconvenience it may cause in normal, everyday life. In an emergency, frozen water is a threat to your health and can cause significant damage to your property.

Frozen water is a prepper's worst nightmare in winter.
Frozen water is a prepper’s worst nightmare in winter. It’s a drain on your body and your potentially limited energy supply.
  • Frozen water is dangerous to consume. We’ve all heard the survival advice to avoid eating snow. The same goes for your frozen water supply. When you chow down on ice, you end up lowering your core body temperature. In a winter survival situation, that can quickly lead to uncontrollable shivers, hypothermia, and death. I’ve written extensively on the dangers of getting cold during a harsh winter right here.
  • Freezing water is a destructive force. People imagine the slowly freezing water in their ice cube trays and don’t immediately think of danger. However, the reality of ice is that it can and will damage or totally destroy whatever you’re storing it in if you don’t prepare it properly. Water expands about 10% when it freezes. Bursting pipes, exploding water bottles, and busted emergency water barrels are just a few common problems with freezing water. If you think a busted pipe is annoying in your everyday life, imagine how devastating it will be in an emergency situation when you’re relying on it for survival.
  • Frozen water is easily contaminated. Water that freezes generally has a high likelihood of becoming contaminated. This is mainly due to the expansion of water as it freezes adding stress to pipes, seals, and other aspects of your water system. Once there is even a small crack in your system, your entire emergency water supply could become contaminated. You won’t even know it’s contaminated until you’ve consumed it and end up sick. Yes, parasites and bacteria can lay dormant in ice and spring back to life once thawed. Since you may not have the luxury of an electric stove, camp stove, or even a basic survival fire, your chances of purifying that block of ice that used to be your emergency water are pretty low.
  • Thawing ice is a huge waste of energy. Right now, you could put an ice cube on your desk and watch it slowly melt. You’re in no rush and the ambient temperature in your home or office is probably quite pleasant. You also don’t need to drink the melted ice; you’re doing this for fun. When you need to turn to your outdoor water supply in an emergency, it is probably pretty cold both outside your home and inside your home. Any method you find to melt the ice that was once your water supply will require significant amounts of energy. Energy you could be using for something else, such as warming up the inside of your home.

Ways to Keep Your Outdoor Emergency Water from Freezing

While indoor storage of your emergency water supply is ideal, I wouldn’t be a very good prepper if I didn’t have some solutions for outdoor water storage, too. Like many preppers, I keep a significant portion of my emergency water stored outdoors in large tanks. The reason I do this is simply because there isn’t a lot of extra space inside my house, and I want to have a lot of water just in case.

Some methods for keeping your outdoor emergency water from freezing take a bit more planning and cost more money, but can yield better results. If time, money, and space are concerns, I have some options for you.

Method 1: Store Your Water Underground

First, you’ll want to check to see how deep the frost depth (also known as “frost line”) is in your area. This is the depth at which ground water is expected to freeze. Builders use this information regularly while planning construction of home foundations and other structures.

You can find this information at your local building department or by checking this website to get a general idea of where the frost depth is in your area. Once you have that depth, store your water below that level so it will be protected from freezing.

Ideas for Water Storage Underground and Below the Frost Depth:

  • An underground water storage tank.
  • Air tight containers (such as 55 gallon drums) of water.
  • Large PVC pipes that are capped at both ends and full of water.
  • Re-supply caches that can include emergency water, food rations, and other items.

For whatever method you use for storing water underground, be sure the top of your container is below that frost depth. You definitely don’t want any part of it peeking above the ground either, so measuring carefully is imperative. When in doubt, bury it deeper than you think you need.

With your water supply safely underground, you won’t be taking up precious space in your shelter. It’ll also be hidden from looters. The main downside to this method is that your water is not easily portable. You’ll also need to have safe and easy access to your underground water storage or you’ll need to build your shelter nearby.

Tip: A bigger tank is better since larger masses of water take longer to freeze.

Bottled water stored upside down in an ammo can.

Method 2: Use a Greenhouse

Even in the winter months, greenhouses are often much warmer inside than the ambient temperatures outside. You can increase the temperature further by keeping a compost pile or open-top bin inside the greenhouse.

Compost piles can reach up to 170 °F. Even if your compost doesn’t get that hot in winter, the smallest increase in temperature can help keep a large water tank just warm enough to prevent freezing.

The greenhouse method also gives you a place to grow food in the winter, sleep in relative comfort, and stay dry in stormy weather. A major downside is that rodents and other vermin will be attracted to the warmth and the compost itself. You’ll need to be on high alert for these nasty visitors.

Method 3: Use Steel Tanks to Absorb Heat

Even if you can’t bury your water tank below ground, there are still ways you can help prevent freezing of your emergency water when it’s above ground. You can use large steel tanks to help absorb heat from the sun, for example.

Make this method more effective by:

  • Ensuring your tank has maximum exposure to the sun. The more sunlight exposure on your water tank the better. Make sure it’s out in the open or some other place where it wont be shaded. Southern exposure is best for those of us in the United States or other countries in the northern hemisphere.
  • Painting your water tank black. Most of us understand that black absorbs light (or energy), while light colors like white will reflect it. Painting your tank black will help ensure that it absorbs the maximum amount of warmth possible from the sun.
  • Insulating your water tank. If you have the means, you can wrap your water tank in insulation from your local home improvement store. In a pinch, you could also use foam, spare blankets, or even old newspapers (as long as they can be kept dry). Any insulation will help to keep in whatever heat the container collects.
  • Positioning your tank so it’s touching the outside wall of your home. Only do this if it is structurally safe to do so, of course (remember, water weighs a lot – over 8 pounds per gallon). Your home is likely much warmer in the winter than outside your home. Having your water tank mounted firmly against the outside wall of your home will help produce a “heat sink” and allow your tank to absorb some of the warmth from the wall of your home. It wont be much since your home is likely well insulated, but every bit helps.

This method will depend a lot on your location and the lowest probable temperatures. As with the underground method, the larger the tank, the slower the freeze. If your area doesn’t get a lot of sun, this won’t be as effective for you.

Method 4: Store Water in Your Car

It’s a no-brainer that you should have a bug out bag (BOB) in your car. Your BOB should always include a personal water supply, but don’t stop there. Keep extra bottles of water in the cab of your car, not the trunk.

When you turn the car on, it’ll warm the water up. The cab will retain that heat for quite some time, decreasing the chances of frozen water. This is especially true if you plan to sleep in the car. Your body heat will help keep the car warm and your water from freezing.

Tip: For the best results, water should be kept on the seats, not the floor.

Method 5: Keep Water in a Cooler

One method I’m particularly fond of in a pinch is using a regular camping cooler. The same properties that keep my beer and soda icy cold in the summer will keep my emergency water unfrozen in the winter. The key to success with this method is to only open the cooler when absolutely necessary—cold air sinks, which means every time you open the cooler, the cold air around you is going to rush inside.

You can open it near a fire or camp stove to “recharge” the warmer air inside, however. If your cooler has a metal lining, you can place a heated stone from your fire inside a can or heat-proof jar, then place it inside the cooler to help keep your water from freezing.

Using Water Additives

In all my years of prepping, I have never found a reliable or safe water additive that will prevent freezing. The biggest issue with using an additive to prevent your water from freezing is whatever you add, you’ll be drinking eventually. Either that or you will need an efficient way to remove the additive prior to drinking it.

  • Alcohol – I’ve read about preppers spiking their water with alcohol, but I’m not willing to try this. It may prevent freezing, but it’s common knowledge that alcohol and cold-weather survival do not mix well. Alcohol not only contributes to poor decision making but it also has lasting effects on your body which can lead to health issues. Alcohol causes the blood vessels near your skin to dilate. That moves all that blood and heat away from your core, lowering your core temperature, inviting hypothermia.
  • Sugar – Some preppers have suggested sugar additives to prevent freezing. To debunk this myth, you have but to look at Popsicles. Most cheap pop-ice treats are literally colored sugar water. Guess what? They freeze just fine.
  • Salt – Lastly, the most cringe-worthy of suggestions is adding salt to your drinking water. First of all—yuck! That’s not going to taste very good. Second, the amount of salt needed to retard ice formation can be dangerous. Every prepper should know that drinking salt water is never a good option. The salt content will contribute to dehydration and too much sodium can lead to heart problems and kidney issues.

Additives just aren’t a smart move, if you ask me. Until I see some scientific research done on reliable (and safe) water additives to prevent freezing, I’m going to skip it. There are plenty of ways to prevent water from freezing without risking kidney damage and dehydration.


Whether you’re planning to store large quantities of water or you need the portable options, you’ll eventually be using a water bottle, canteen, or thermos. Water freezes from the top down. So store those personal water containers upside down, with the lid at the bottom. If your lid or drinking spout is facing up, guess what’s going to be frozen solid when you need a sip?

Hopefully, you’ve learned some new tricks or I’ve been able to pump up your creative juices for winter water storage ideas. I’d love to hear your tried-and-true methods in the comments, too.

What challenges are you running into while storing your emergency water outdoors? Share in the comments so other preppers can help!

John Walter

John Walter is an emergency preparedness consultant with eight years of experience and training in related fields. He is a passionate prepper living in the Sacramento area of California.

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