How Long Can Water Be Stored For? Is It Safe After 1 Year?


How long is stored water good for?

I received an email basically asking how long can water be stored for.

I was asked for my opinion about the safety of drinking water that has been stored for a year under specific conditions. Including being exposed to higher than normal temperatures during the summer.

Here is the question and my answer.


Water from a city municipal system which is treated and filled into a clean BPA-free 55 gallon dark blue barrel.

Bungs are tightened and sealed and the barrel is placed out side, siting on bricks to allow for air flow.

Outside temps during the summer months are about 105 degrees F for roughly 3 months.

Would that water be safe to consume after say about a year?

Or would you recommend treating for the purpose of consumption.


If Water Storage Conditions Are Right

If I was confident that I had cleaned and disinfected the BPA 55 gallon barrel ahead of time,


If I was confident that the water source was not contaminated (municipal water typically purified with at least 1ppm chlorine) – use swimming pool chlorine test kit to check this,


If I was confident that the barrel had remained sealed through the time period,

I would not be terribly worried about contamination after one year.

Heat, Sun, Algae Growth?

One potential concern in the example above is the heat. This might speed the rate of algae growth. But only if there were microorganisms in there to begin with that were not eliminated due to not enough chlorine (for example).

If it were me, I would initially boost the chlorine level to ~ 3ppm.

Water-Bleach Ratio for Drinking Water Purification

Algae also likes sunlight. If the water storage container is opaque (e.g. the dark blue color), this reduces photosynthesis.

The person did not say whether or not the containers were in direct sunlight. I would advise to shade them in some way.

Use A Water Filter

Pro Tip: If you are storing water for preparedness, then you really should have a Berkey Water Filter! This will insure a tremendous peace of mind while drinking that water (or any water).

Check out all of the Berkey models at their their U.S. authorized dealer:


Can Water Go Bad?

Many people are under the misconception that water can go “bad” over time.

The thing is… water is water is water.

Safe drinking is about the contaminants.

If the water is not contaminated to begin with,

and sealed in a clean non-contaminated environment,

and so long as there are no contaminants that enter the environment,

It will theoretically be safe forever.

Replace it every year?

Given the conditions mentioned (exposure to high temperatures during the summer months,) I would replace the water each year. It’s not that difficult to do for peace of mind.

IF there had been any organic contamination within the barrel, the heat from the summer months could increase the likelihood of bacteria/microorganisms growing. Especially if the chlorine level gets too low. Also, chlorine will break down with heat and sunlight.

Side Note: Chlorine (bleach) has a shelf life and will lose its potency over time. When it breaks down, it basically turns to a salt, so as a rule-of-thumb regarding your regular household bleach, I would replace it each year.

Another reason to replenish the stored water: The water will taste ‘flat’ over time. Though the flat taste can be somewhat remedied by pouring the water back and forth from one container to another to reintroduce more oxygen when its time to drink it (aerated).

Purify Water for Safety

IF you suspect for any reason that the water might be unsafe to drink, then by all means, purify it before drinking! The safest way is to boil it.

You can also purify water with ordinary ‘regular’ household bleach.

There are many ways to purify water to make it safe to drink,
including the methods mentioned here…

The Smallest Berkey Countertop water filter – Specs

Big Berkey


  1. I just emptied one of the 30 barrels of water I stored June, 2011 with no additives –just water from the tap.
    I did use the Berkey and it was fine.
    The barrels were pristine when opened, but have assumed a little mold after exposed to air.

  2. In 2018, I bought a 55 gallon water barrel, rinsed it with a light bleach solution, filled it with r/o water, and added Aqua Mira treatment. It has been sealed since, and resides in our bunkhouse. As you say, in theory, it should be good forever.e

  3. We have three barrels in our barn, purchased a chorine based chemical from amazon that is supposed to keep it “safe” for three year, who knows? Would most likely run it thru our Berkey if drinking, or use it for gray water to flush/wash/ bath.

    1. Can you tell me what the product that you purchased on Amazon was?

  4. Even though we have a well, we store emergency human drinking water, animal water and everything else water. All the containers are food-grade. We have hot summers and mild winters. When we have to use the stored drinking water we run it through our trusty water filter first.

    We store both drinking bottled water and drum water. Human water is stored in new (never used for anything before our use) 55-gal blue drums with sealed lids and only a bung opening. These are filled with well water. They are inside the garage sitting on pallets. We test the water once a year and if needed we empty and clean the barrels during the summer months. We use powdered bleach mix to keep the nasties out.

    The animal water is stored in used jalapeno drums with removable, lockable lids. We also have 300-gal tote containers previously used to transport coke syrup. We cleaned them first with a pressure washer and bleach, then sun dry them before our use. They are on concrete blocks near or against various out-buildings.

    The remaining barrels and totes of water are used for washing, cleaning, flushing and rain catchment and are scattered around the farm. They all sit on concrete blocks and have hose adapters for ease of use.

    This may sound like over-kill to you, but try running a homestead without water! When the electricity goes off or well pumps break down, using the stored water is easier than hand pumping from the backup well. We also help our neighbors until they can get their wells repaired. Ya just never know when something will happen but knowing you have a backup keeps you sane.

  5. We are on a well. We also have a 130 gallon tank in the house along with 4 , 5 gallon water jugs and some case water. Our goal was a 30 day supply for two. We do have a year round stream and a year round spring , but this requires water transport . We do have a Berkley .

  6. If the SHTF, the last thing you want is a case of the squirts! My plan will be to boil the stored water, treat it with chlorine, and run it through a filter. Why take the chance when you don’t have to?

    Oh; and the squirts; antidiarrheal; reeeally important…

      1. Soylentgreen is one of those Greens that is hard to grow in the garden. But it is definitely an acquired taste.

    1. Exactly. Risks are things you only take when you have to. The better prepared you are, the fewer risks you need take.

  7. I have a 1500 gal cistern from my slow well. I use the Berkley type water filter for drinking water and cooking etc.

  8. So, if I am filled immediately emptied Distilled water jugs, right from the city tap, and put the lid on immediately, then store out of sunlight…Likely good for a year..right?

    1. Jane Foxe;
      Do not necessary need to be Distilled Water Jugs.
      But basically yes, unless it’s left to freeze and breaks the jug
      Or you run it over with a Lawn Mower.
      Or ……. never mind, you get the idea hehehe

    2. Please be aware that plastic 1 gallon water hugs you get at the store are designed to break down and biodegradable over time. Somewhere near 1 year. I have had 1/3 of them start leaking after 1 year stored in room temps.
      Plastic pop and juice bottles last a lot longer and are highly recommended over the thin biodegradable 1 gallon water hugs.

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