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

How Long Can Water Be Stored For? Is It Safe After 1 Year? by  for Modern Survival Blog

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.

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Ken Jorgustin

Ken Jorgustin’s survival blog focuses on a wide variety of preparedness topics varying from short to long term actions and solutions for wide-ranging scenarios of preparation… for daily life, disaster, or even SHTF collapse. Subjects include situational and risk awareness, the dangers, systemic risks, and avoidance of dependence upon the major ‘modern’ systems that we take for granted, topics of self-reliance and self-sufficiency, and practical solutions to live a way of life while surviving these uncertain times. Modern Survival is Preparedness For Life Preparedness is a process and will become a way of life – one in which you have more control over your own destiny. Being better prepared will help liberate you from “the system” which in many ways is designed to hold you down and keep you “dependent”. Modern Survival Blog has been committed since JAN-2010 to produce a wide variety of information to hopefully provide you with ideas for your own preparedness.