Water is a basic human need and key to survival. Methods to gather, store, and sanitize water are all important, but knowing how much water you may need is important as well. Water is heavy and takes up a lot of space when it is stored, so knowing exactly how much you need can help you plan for preparedness.
That’s why we’re going over the gear that can help you store, filter, and sanitize water, as well as sharing a calculator (and the general math behind it) that will help you store the correct amount of water based on your needs and renewable resources.
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How to Collect and Store Water
Gathering and storing water is no small task. Water is bulky and heavy, and liquid is generally hard to store. You can only store so much water until it becomes unreasonable to keep it treated, rotated, and fully reliable, so water collection methods are important for long-term plans.
A few ways people collect water at home include:
- Rainwater Collection – extremely popular with preppers, rain barrel systems can work in a wide range of applications and can use your roof area to collect massive amounts of water whenever it rains. See our top rain barrel picks from our review roundup.
- Wells – one of the oldest and most reliable methods is well digging. It may require a homestead or rural plot, but wells make you more self-sufficient when you are not reliant on city/suburban water mains.
- Water Generators – if you can tackle the cost and energy requirements, AWGs pull water straight out of the air, purify it, and serve it to you however you want it. See our top atmospheric water generators from our roundup.
Some of the top home storage methods include:
- Water Bottles/Jugs– Easily bought and stored from grocery stores, they make for easy, shorter-term water storage.
- Temporary Storage– tools like the WaterBOB, or just gathering water in storage containers and bathtubs, can be helpful when preparing for impending disasters.
- Water Bricks and Drums– Reusable large water storage containers are ideal for preparedness, ranging from 3 months to a year.
There are other great ways for collection and storage, like dew collectors and giant water tanks- but those are less common than the methods above.
Bug Out Bag Water Gear
Water weighs 8.35 pounds per gallon (or 1 kilogram per liter for the rest of the world). Anyone familiar with backpacking can tell you that this is not very forgiving when you need to carry water on the go.
Bug out bag water is not just a weight concern, but also a packing problem. A gallon of water takes up 231 cubic inches- which is a huge displacement compared to your survival gear!
Water is not the best way to utilize your limited bug out bag space (or weight). If you throw a couple of gallons in your backpack, you’re going to severely slow yourself down.
Still, water is a requirement for survival, and you need to have solutions with you even on the go. There are several options when it comes to keeping water on the go. One crossover from Everyday Carry (EDC) is the personal water bottle.
Bottles
Stainless bottles may have more weight and take up more space when empty, but they give you the option to purify your water by boiling it. If you don’t have another method of purification or need a backup method, stainless bottles are the way to go.
Mainly, you want to steer away from the insulated Yeti and Stanley models since you will want to be able to use the bottle for boiling. There are plenty of models that offer these from reputable brands like Hydroflask and Kleen Kanteen, just to name a few. We’ve tested them and share the best survival water bottles in our review.
Filters
We’ll discuss filters in-depth later, but personal water filters are essential in any mobile survival kit. Filters that allow water to be pumped, plunged, or squeezed are much more versatile than straw filters since you don’t need to drink the water as you are filtering.
Survival filter bottles, usually from filter companies, are plastic bottles with integrated personal filter straws (with a few exceptions). While they sound like an ideal solution for survival, they can be more limited in their use than steel bottles, so it’s not the first solution we recommend.
Additional Gear
Besides the two main essentials, drink mixes, bagged water, and collapsible containers can all be useful in mobile survival kits. Electrolyte powder can help with dehydration. Emergency water pouches are great options for car survival kits and other kits where you want to store water for long periods without rotation. Collapsible containers give you more water storage when you set up camp, without adding much weight or displacement when you are on the move.
Water Storage Calculator
Water is an extremely important resource during emergencies and disasters, so it is always a good idea to know where you stand beforehand. That’s why we developed both an embedded calculator and a more in-depth spreadsheet calculator- to make it easy to understand how much water you need depending on the length of time and the number of people you are planning for.
Excel Water Storage Calculator
We have our larger calculator as a downloadable spreadsheet over on our Patreon page. You can buy the spreadsheet for $3, or it’s free for our Patreon subscribers.
This calculator has specific storage containers added and treatment types, so you can see not only how much water you need to store but also the supplies you’ll need on hand to treat that amount of water.
How Much Water Should You Store for Emergencies?
30 gallons per month, per person, is the consensus of the CDC, FEMA, and most emergency management agencies.
While the amount of water that you need depends on your planned uses, they break down pretty easily:
Drinking- People generally need 15 gallons of clean drinking water per month. Your body is constantly losing water through sweating, digestion, and even breathing. You will need an ample supply of water to prevent dehydration.
Cooking– About seven and a half gallons of water are needed to use for cooking per month. Most freeze-dried food kits require water for rehydration. Water is also needed to activate MRE heaters. Boiling is an effective cooking method that requires water as well.
Washing– Hygiene is important during emergencies, and seven and a half gallons are needed to keep clean, wash hands, and for first-aid use.
If you use the calculator above, you can plan ahead using these amounts to find exactly how much water you need to store.
How Frequently Should Water Storage be Rotated?
The storage container type, condition of the water, and conditions of the storage area all affect how often you should rotate your water supply.
Different types of plastic storage containers are effective for different lengths of time. BPA-free plastics are preferred for long-term water storage because BPA can leach into the water, and BPA mimics estrogen and can affect your body.
Purified and/or treated water is best for storage and would only need to be rotated out every five years. Still, it should be checked for algae growth or any contaminants, or murkiness annually. Any sort of film or discoloration is an easy way to tell that you need to rotate the water out.
Water stays best in airtight, watertight containers stored out of sunlight in a room-temperature setting. Temperature fluctuations can encourage bacterial growth, compromise the seal on containers (through pressure release), and degrade plastics. If you are not storing water in ideal settings, you will need to check the water more often and rotate it out more frequently.
How to Sanitize Water
Sanitizing water is a very important skill to learn, and it is easiest with a few resources. There are many different methods, but most methods revolve around first filtering the water of contaminants and then treating the water, creating a two-step process. Most people treat water with bleach, tablets, or drops- but there are also newer methods using UV light.
Sanitizing with Filters
Different types of filters have varying degrees of effectiveness. Filters count as anything from a mesh keeping leaves out of your rain barrel to a sophisticated reverse osmosis filter.
Even high-filtration devices (like osmosis filters and survival filters) will need treatment when preparing water for long-term storage. Water storage needs to be treated to prevent growth, not just to immediately provide clean water.
Filters come in a wide range of sizes, from portable personal filters to in-place or installed and powered filters. We’ve tested dozens of filters and share results in our best emergency water filter review.
Some contaminants, like radionuclides, can only be filtered out by reverse osmosis (RO), so be aware of your filtering limitations based on the threat you are facing.
Luckily, portable reverse osmosis water filters are becoming realistic and affordable thanks to some innovative companies.
Treating with Bleach
Using typical household bleach (non-scented), the amounts the CDC recommends depend on whether the water is clear or cloudy.
| Amount of Water | 1 gallon | 55 gallons | 300 gallons | 1000 gallons |
| Bleach for Clear Water | 8 drops | 2 1/2 tablespoons | 3/4 cup | 2 1/2 cups |
| Bleach for Cloudy Water | 16 drops | 5 tablespoons | 1 1/2 cups | 5 cups |
Bleach is a versatile chemical for emergencies, making it one of the preferred water treatment methods. The main downside is that bleach does not last long in storage- it starts degrading after just 6 months and loses most of its effectiveness after 18.
Treating with Tablets or Drops
Purification tablets or drops make water sanitization even easier. Treatment times vary, but most tablets are formulated to treat one liter of water. That’s one reason why we recommend your water bottle in survival backpacks to around 34 ounces (1L). We’ve taste-tested and evaluated almost every tablet or drop treatment method and share the results in our best water purification tablets review.
The Next Step
Emergency water storage should be a priority for everyone, just like prepping. If you are unfamiliar with prepping or what preppers are, check out: What is Prepping and What is a Prepper?
Hopefully, our water storage calculator helped you determine how much water you need to store or helped you verify your current water storage. The survival rule of 3 states that you can’t go much past 3 days without water, so it’s best to use 3 days as a starting point if you are just starting out with the calculator and water storage.
Once you have water storage down, start to stock up on food.
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