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Water Storage Calculator: How Much Water Should You Store?

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Water Barrels

When it comes to storing water, it can be stressful to know how much water is enough. There are so many important uses for water that it can get overwhelming to try to account for them all. In this article I have broken how much water you should store down in multiple ways so that you can take everything into account to make sure you and your family are ready. 

The most basic recommendation for how much water you should store is 3 gallons per person. This will cover your needs for drinking, cooking, and basic sanitation for 3 days. A more comfortable and confident supply would be 14 gallons of water per person or 1 gallon per person per day for 2 weeks. This will give you a much better supply should there be a larger emergency or other needs arise. 

When planning your water storage, there are many things to take into account. These basic recommendations provide only ½ gallon for drinking, ¼ gallon for cooking, and ¼ gallon for sanitation per day. There is no room in that gallon for a shower, extra drinking water, making extra food, or first aid needs. So, keep this recommendation as the starting point but plan to store more to give yourself plenty of wiggle room. Another important point is to know how long water can be stored for before going bad.

Water Storage Calculator

Water Storage Calculator Chart: 1 Gallon Per Person Per Day 

1 PERSON1 Gallon2 Gallons3 Gallons4 Gallons5 Gallons6 Gallons7 Gallons
2 PEOPLE468101214
3 PEOPLE36912151821
4 PEOPLE481216202428
5 PEOPLE5101520253035
6 PEOPLE6121824303642

Storing Water for Drinking 

50 Gallon Water Storage Jugs

The number one reason for storing water is hydration. You can become dehydrated in a matter of hours which makes it crucial to have enough water on hand for each person in your household. Basic water needs will vary for each person and situation. Pregnant or nursing women, sick people, or those that live in warmer climates will need more water on average.

The CDC recommends storing 1/2 gallon of drinking water per person per day for 3 – 14 days. This is based on the 8×8 rule, drinking an 8 oz glass of water 8 x a day to give you 64 oz or ½ gallon. Again, this is only a minimum suggestion and your actual water intake could vary significantly based on your lifestyle and physical health. 

A great way to tailor this advice to you and your family is to start by tracking how much water you drink in a day. You can use one large water bottle or keep a count of how many glasses of water you drink throughout the day. Do this for a few days and take the average. Multiply this average out for a week or a month to see how many gallons you will personally need to store to maintain your water intake. 

Here is an example of what this could look like:

Water Intake Total Water
Day One6 cups x 8 oz48 oz /
Day Two8 cups x 8 oz64 oz
Day Three5 cups x 8 oz40oz
Day Four7 Cups x 8 oz56 oz 
Average Water Intake: 52 oz per day or about ⅓ gallon

According to the chart, this person would need to store at least ⅓ gallon per day for drinking. To have a 1 week’s supply this would round up to be 3 gallons per week or 6 gallons for a 2-week supply of drinking water. 

Keep in mind that this number is just a daily average. If your circumstances, health, or lifestyle change, so could your water intake. Pregnancy, nursing, sickness, stress, the environment, and even how well you sleep can all change how much water you need.   

Storing Water for Sanitation

Rain Barrel

In a true emergency, water may not be available for an extended period of time, and it will be increasingly important to keep yourself clean and healthy. Washing and sanitation can take up a ton of water if you are not careful, so make sure to have enough on hand as well as the know-how to keep up your personal hygiene without wasting precious water.

The recommendation on how much water to store for washing is ¼ gallon per person per day. This would let you wash your hands a few times, but little else. Increasing this just to ½ gallon per person per day could allow you to save up water over a few days in order to bathe, shower, or wash clothing. This all depends on personal comfort levels, so take this into account when planning for extra water. 

Another very important sanitation use for water is any first-aid needs. If you need to wash out a wound, cool a burn, or treat heatstroke you will need plenty of cool, clean water. This water can be stored as one supply for the whole family as you will hopefully not need to use it for every person. 

Storing Water for Cooking

Take a look around your food storage and try to figure out how much water the average meal would take. Do you have a lot of pasta, oatmeal, or rice stored? This will take more water. Are there cooked canned meats and premade soups? These already have water so you will not need to store extra. 

Find a balance between meals that take more water and those that don’t so you don’t run out too fast. 

Also keep in mind that if you are storing ¼ gallon of water per person per day, you have that amount of water from each person for cooking together. So a family of 4 has an entire gallon for cooking each day, which is very doable. 

If your food storage is made up of MREs or all freeze-dried meals, then you will need to make sure you have enough water to make them all. They all cook individually so you will not be able to combine your water storage as a family as easily. 

The average MRE or freeze-dried meal takes anywhere from ⅓ to 1 cup of water per meal. This can add up quickly if you are depending on these meals 3 x a day. Shoot for a mixture of these types of meals plus food that takes less water to prepare. 

How Much Total Water Should I Store? 

There are so many considerations to take into account when deciding how much water to store for you and your family. Here is a checklist of things to think about and how much water to add per person for each category: 

Per Person Per Day (Gallons)Per Person Per Day (Ounces)
Drinking½ Gallon64 oz
Sanitation½ Gallon 64 oz
Cooking¼ Gallon 32 oz
First Aid¼ Gallon16 oz
Emergency Sickness⅛ gallon16 oz
Dogs or Cats ⅛ Gallon 16 oz 

Backup Water Supply – Filters

Making sure you have enough water on hand for every scenario can be a bit overwhelming, especially when you just want to keep your family safe and well. Having backups for your water supply can give you the peace of mind that you will have enough water even if your storage runs out.  

The most beneficial backup for your water supply will be a high-quality filter. These can be in the form of a straw filter, a large water purifier, or anything in between. Just make sure that you know how to use it and have enough for each person in your household.

Check out this post for my recommendations on straw water filters: Best Emergency Water Filter Straws – My Top Picks! (

FAQ – How Much Water Should I Store? 

I have a large family and these gallons are adding up fast! How do you store large amounts of water? 

There are a couple of options for optimizing space while also storing large amounts of water. Check out my post for the complete guide! How Do You Store Large Amounts of Water? (

Should I store everyone’s water in one large container or in separate gallons to keep track better?

When the day comes and you finally need to use your emergency supply of water, it is going to be crucial that you keep track of how much water you and your family are using.

A simple way to do this is to have one large container with the majority of your water storage and then 1 or 2 gallon jugs for each member of your family. This way each person can refill their gallon each day and will know exactly where they are with their water usage.

You could also put a chart next to your main water supply to track who has gotten their water each day, so you can make sure everyone is on track! 

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Hi! I’m David. For most of my life I have been interested in emergency preparedness. Over the many years things have changed a great deal. From freeze dried food, to LED lanterns, preparing for an emergency has never been easier. The continual research I have done over the years has become the basis for this website. Now it is one of the most trusted sources to learn about emergency preparedness.