How Long Can Water be Stored Before it Goes Bad?

How long can water be stored before it goes bad?

Water is one of the fundamental necessities of life so there is no supplement or replacement for water. I think we sometimes take water for granted and this would become evident if you ever find yourself without fresh drinking water. Going thirsty is not an enjoyable experience, especially extreme thirst. I was looking at our water storage container the other day and couldn’t help but wonder, “How long can water be stored before it goes bad?”

The length of time potable water can be stored safely ranges anywhere from a single day to indefinitely depending on how you are storing the water and the purity level of the water, to begin with. Clean water that is left in an open cup outside is likely to go bad (become contaminated) within 1-3 days. Water from your tap (assuming that it is clean enough to drink) that is stored in a sealed container can last up to 6 months or maybe longer, however, it may be a good idea to check and add a small amount of household chlorine bleach to purify the water (do not use bleach that has fresheners or scents). Purified water that is sealed in a food-grade container will last for a long time, 2 years, or even much longer.

The Estimate amount of time before clean water goes bad (becomes contaminated)

Water Storage TypeAmount of time before contamination
Open cup1-3 Days
Self-sealed containers, barrels, drums, or jugs of clean tap water6-12 months + (check regularly and replace)
Purified water sealed in a food-grade container2 years + (if stored properly)

How long can you store water in a 55-gallon drum?

Potable water that is being stored in a food-grade 55-gallon drum can be stored safely for up to 1 year or even longer under the right circumstances. To store water in a 55-gallon drum or barrel safely for 1 year or longer a clean food-grade drum must be used, it must be tightly sealed to keep out light and chemicals, kept in a dark cool location and off of concrete, and not accessed improperly. Additionally, if treated regularly (roughly every 6 months) with the correct amount of household chlorine bleach or a water purifier is used it can store for much longer, however, if possible I always replace my stored water every year.

Does stored water go bad?

If properly storedwater will not spoil. The contamination that gets into it is what actually makes water go bad. In theory, your water could store and stay good forever if you take the proper precautions by sealing and storing your water so that bacteria or other contaminants don’t get into it and cause it to go bad.

Let’s clear up something minor really quickly. Water itself doesn’t actually go bad. The truth is that it can and does become contaminated over time. Bacteria, Algae, and other Pathogens are often what contaminate water storage and cause it to “actually go bad”. This contamination can happen in many different ways to various degrees of severity. 

It is critical that you know how to safely and easily purify water at home in case your stored water or other water sources become contaminated. Also, for those who have colder season like us see how to keep water storage from freezing outside.

Can water be stored indefinitely?

Potable drinking water can be stored indefinitely if stored properly in food-grade containers that are stored in a dark cool environment. Chemical treatments (including household bleach or iodine) can be used every 6 months to a year to keep the water potable. However, the best practice is to drain water storage, clean containers, and replace them with new potable water about every two years or sooner.

Containers, including food-safe plastic containers, leach chemicals into the water storage but haven’t shown to cause any serious health problems. However, if left in a hot environment like a garage or car in the summer the water will not taste very good and is at a higher risk of contamination.

How to Store water to prevent it from going bad

The Federal Emergency Management Agency (FEMA) recommends storing tap water in clean plastic, glass, enameled metal, or fiberglass containers. Once you have filled the container, it should be tightly sealed and stored in a dark, cool location. See our top 13 water storage container ideas!

Water storage conditions to prevent it from going bad include:

  • Start with clean potable water
  • Store in clean food-grade plastic, glass, enamel-lined metal, or fiberglass containers
  • Tightly seal the container to keep out light and chemicals (covering water storage with a tarp could be a good idea)
  • Store up off of concrete, away from chemicals or anything that you wouldn’t want to leach into the water, and keep in a dark, cool location

How can you tell if your water has gone bad (become contaminated)?

Your water storage may be contaminated if

  • It has a strange smell
  • Is murky
  • Developed a strange color
  • Green algae growing in it
  • Has floaties

Consciously make your best judgment call. Inspect your water storage about every 6 months to determine if it should be treated or replaced. If you are sure, it is simply best to dump out the old water, clean the container, and refill with clean water.

Use a Water Filter

Stored water that has become contaminated can be purified and made into drinking water again. I always keep a couple of new water purifiers accessible for any emergency situation. If I’m unsure of my water storage purity then I will definitely use a water purifier or purification method before drinking. I always keep a small water filtration straw and a larger water purifier accessible for any circumstance. In a go-bag and at home. It can be helpful in an emergency and you are unsure if your water storage has been contaminated or not.

Knowing which water filter to get can be difficult so check out our article Selecting the Best Emergency Water Filters: Buyers Guide.

I use a water filter when drinking from my water storage if I’m unsure of water contamination. I keep several of the below water filters in different locations so that I can easily have access to them whenever needed.

By far my favorite mini water filter straw is the Sawer mini straw (Check the price on Amazon). It is better than the Life Straw because it will filter up to 100,000 gallons of water and the Life Straw will only filter up to 1,000 gallons of water.

I also own a couple of Survivor Filter Pro – Hand Pump Water Filters (Check the price on Amazon). I like this hand pump filter the best for water storage because I can easily drop the receiving inlet hose in my water storage and pump out clean water without moving, tipping, or sticking my hand in the container.

Can you get sick from drinking old water?

You can get sick from drinking old water. However, the reason for getting sick is not because the water is old but because of Bacteria, Algae, and other Pathogens getting into the water source. So getting sick from drinking old water depends on how the water was stored and how clean it was in the first place more than how old it is.

For example, you are much more likely to get sick from drinking old water that has been sitting outside in an open cup or bottle for a couple of days than by drinking a sealed, unopened bottle of purified water that is a couple of years old.

3 Ways water storage can go bad (become contaminated)

  1. Bacteria or Algae was initially in the water before being stored in a container 
  2. Contaminants leaching out of the container into the water storage
  3. Accessing the water storage improperly 

 Bacteria or Algae

does stored water go bad? can you drink water that has algae and bacteria in it?

Is your water storage green, smells funny, or has floaties? Your water storage may be contaminated. It is easy to identify Bacteria or Algae contaminated water if the water has been sitting stagnant for a few weeks. For example, if you were to leave a bucket of water outside for a few days you would come back to find that the water in the bucket contains mosquito larvae, algae, and various other life forms, none of which you would want to be drinking.

Contaminants leaching out of the container into the water storage

The second way for your water storage to become unfit for drinking is for something to leach out of the container into the water. For example, if you were to store water in a lead container it would leach into the water and make it toxic. It’s important to not store water in containers that are not food grade. The reason it is so important to use food-grade containers is that some containers (like lead or an old container of pesticides that hasn’t been properly cleaned) will actually leach toxic chemicals into your water storage which will be the cause of contamination. According to the CDC (Centers for Disease Control and Prevention), it is preferable to store clean drinking water in plastic, ceramic, or metal containers.

Accessing the water storage improperly

The third way that your water storage can become contaminated and go bad is by sticking your hands or other objects that could have bacteria on it in your water to access it. The CDC suggests that your containers have the following characteristics:

  • A small opening with a lid or cover that discourages users from placing potentially contaminated items, such as hands, cups, or ladles, into the stored water;
  • A spigot or small opening to allow easy and safe access to the water without requiring the insertion of hands or objects into the container; and,
  • Size appropriate for the household water treatment method, with permanently attached instructions for using the treatment method and for cleaning the container.

Teach all family members how to properly access your water storage. Be cautious and don’t be the reason that your water storage becomes contaminated and goes bad.

Sanitizing Water Storage

If your water storage isn’t green and growing algae or if it doesn’t smell really bad then you can simply sanitize it. It is important to remember to purify your water storage routinely. A good way to sanitize your water storage is by using bleach.

How much bleach should you add to drinking water?

  • Add 8 drops (⅛ teaspoon) of household liquid bleach for every 1 gallon of clear water
  • Add 16 drops (¼ teaspoon) of household liquid bleach for every 1 gallon of cloudy water

Clear Water

According to the CDC (Centers for Disease Control and Prevention) add 1/8 teaspoon (8 drops or about 0.75 milliliters) of household liquid bleach to 1 gallon (16 cups) of clear water.

Cloudy Water

The CDC also suggests adding 1/4 teaspoon (16 drops or 1.5 milliliters) of household liquid bleach to 1 gallon (16 cups) of cloudy water.

*Treating water with household bleach containing 5.25-8.25 percent chlorine

*Do not use bleach that has fresheners or scents.

This table shows how much bleach is needed to purify/disinfect 1,000 gallons, 300 gallons, 275 gallons, 50 – 55 gallons, and 1 gallon of water.

Water Amount1,000 Gallons300 Gallons275 Gallons50 – 55 Gallons1 Gallon
Bleach to Clear Water2 & 1/2 cups3/4 cup2/3 cup 2 Tablespoons & 1 teaspoon8 Drops
Bleach to Cloudy Water5 cups 1 & 1/2 cups1 & 1/3 cups5
16 Drops

Water storage that lasts longer

One easy way to store water is to buy purified drinking water in gallon plastic jugs at the grocery store. This water is inexpensive, free of bacterial contamination and is sealed in a food-grade container. You can store this water indefinitely but make sure to check on it periodically incase the container wears out or has some kind of breach.

store bought and manufacture sealed water bottles for water storage

Another option is to buy packages of bottled water that should last for years just like the gallon jugs mentioned above. I find it useful to store at least 2 weeks of drinking water in store-bought water bottles that I drink on a daily basis and rotate through.  

Periodically clean your old water storage containers

It is always a good idea to clean a new water tank or container before storing clean water in it. Additionally, it would be wise to periodically clean old water storage containers. You can use the old water in your yard or something useful and put new clean water in after you have cleaned the container.  

The CDC suggests that you use these steps to clean and sanitize water storage containers:

  1. Wash the storage container and rinse completely with water.
  2. Sanitize the container with a solution made by mixing 1 teaspoon of unscented liquid household chlorine bleach in one quart of water.
  3. Cover the container tightly and shake it well. Make sure the sanitizing bleach solution touches all inside surfaces of the container.
  4. Wait at least 30 seconds and then pour the sanitizing solution out of the container.
  5. Let the empty sanitized container air-dry before use OR rinse the empty container with clean, safe water that is available already.
  6. Pour clean water into the sanitized container and cover with a tight lid.


It is so important to be aware of how long you can store water in different kinds of containers and under different circumstances. Water is such an important and overlooked asset that we should all store to sustain our families lives in case of an unforeseen emergency. I hope that this article has been helpful and encourage all of you to store at least 2 weeks of water for each member of your family. Good luck!

Looking for help getting started with food and water storage? Check out EZ-Prepping’s Water Storage Calculator and our Food Storage Calculator

Colton Blair

I'm Colton Blair, co-owner of EZ-Prepping with my wife Kaycee. I value the safety, protection, and well-being of my family above all else. Finding easy and practical ways of prepping for emergencies or unexpected disaster has become very important to me.

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