Water Purification Methods

This post is part of a series of more detailed information on water storage frequently asked questions which includes posts storage containers, alternate sources of water, water purification methods, and more. If you are just getting started in preparedness, we recommend visiting our BabyStep 2: Water page for some basic info on water storage.

waterPurification

Contaminated water can contain parasites as well as microorganisms that cause disease such as dysentery, typhoid fever, salmonella, giardiasis, and hepatitis as well as having a bad odor and taste. You should purify ALL water before using it for drinking, food preparation, or hygiene. NO WATER CAN BE PRESUMED SAFE! Before you begin a purification process, it’s a good idea to strain the water through some sort of filter such as layers of paper towel or a coffee filter to remove any large particles. There are many ways to purify water but none is perfect. Often the best solution is to use a combination of these methods.

Water Purification Methods

Boiling

Boiling is the most common and safest method of purifying water. Bring water to a rolling boil for 3-5 minutes, keeping in mind that some water will evaporate. Let the water cool before drinking. Boiled water will taste better if you put oxygen back into it by pouring the water back and forth between two clean containers. (or you can add in some of your stored flavorings such as fruit drink powders, kool-aid, hot cocoa, etc.)

Disinfection

According to the American Red Cross, “The only agent used to purify water should be household liquid bleach.” Add 16 drops of bleach per gallon, stir and let stand for 30 minutes. If the water does not have a slight bleach odor, repeat the dosage and let stand another 15 minutes. Do not use scented bleaches, color-safe bleaches, or bleaches with added cleaners. This method is highly recommended as a backup in case fuel is not available for boiling or distilling water.

Distillation

Distillation involves boiling water and then collecting the vapor that condenses back to water. The condensed vapor will not include salt and other impurities such as heavy metals and most other chemicals that are not removed with boiling or disinfection. To distill, fill a pot halfway with water. Tie a cup to the handle on the pot’s lid so that the cup will hang right-side-up when the lid is upside-down (make sure the cup is not dangling into the water) and boil the water for 20 minutes. The water that drips from the lid into the cup is distilled.

Water Filters

There are two types of water filters, inexpensive travel water bottle filters and gravity carbon filters. A travel water bottle filter is great to throw into your disaster kit, but in cases of extreme contamination you would still want to add in a few drops of iodine or bleach. If you opt for a gravity carbon filter such as the AquaRain or Berkey ones, it MAY be enough purification, but we still recommend to use one of the other methods as well. It can never hurt to be too safe. If you are conserving fuel or on the run, a filter can definitely be a great option and is MUCH better than no purification at all.

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Water Purification Methods


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  • jenjim4

    Alright, so just to be completely clear. I can store regular tap water in juice containers and glass containers. I do not have to treat it if I plan on switching it every 6 months. If I keep it a year plus I would have to either add bleach drops or boil it before, right?

    • Bleach will evaporate out of the water after a year or so. If you store
      water longer than a year you will want to plan on sterilizing it again
      if/when you use it.

      • natalie

        And the bleach also goes inactive after 3-6 mos. So you need to buy new bleach every 3-6 mos (which really irritates me, since then I have a small bottle of bleach to dispose of and it’s a chemical) and you need to replace and put new bleach into your containers every 6 mos. I was told that I needed to add about 8 drops of bleach per gallon of water in my area (portland, or) b/c the chlorine in our water is not enough to keep the water safe for long-term storage.

  • Dcyery

    We have a pool and I was wondering about using that water if necessary, any thoughts.

    • KE4JSX

      Pool water is fine for flushing, bathing or washing clothes. DO NOT use it with anything that goes in your mouth (ie: toothbrush, eating utensils/cups). The chemicals in a pool were deigned to be ingested.

      • KE4JSX

        Sorry. That was supposed to read ” not designed to be ingested” IPod spell checker will be my excuse ; )

  • Gahag28

    Under ADDITIONAL RESOURCES…..clicking on WATER STORAGE/PURIFICATION HANDOUT has continually closed my email out completely. Is some sort of bug attached to that ???

    • It is just a pdf file hosted on someone else’s server. I have never had problems with his websites or with that file. It may just be a large file that freezes up your computer. If you are interested I can try to email you a copy of the pdf file directly. Just let me know!

  • Thanks for the tips on the water filters guys.

  • At least once a year. Every 6 months if you feel ambitious. 🙂

  • Wendy Lloyd

    If I collect and fill up liter pop bottles with water from my tap which is chlorinated…. How often would I have to change the water? I am a little comfused.

  • Wendy Lloyd

    If I collect and fill up liter pop bottles with water from my tap which is chlorinated…. How often would I have to change the water? I am a little comfused.

  • I was wondering if I buy my water at the local water store here in town and keep rotating it to always have a 2 weeks supply since its only 25 cents a gallon do I still need to worry about this?

    My thoughts on this:

    In the water PDF linked above, I talk briefly about some of the plastics used for common water bottles you can get from the store. Whatever you do, don’t get the kid that are shaped like milk jugs. Avoid them like the plague.

    I like the sturdy Arrowhead kind of bottles since they’re stackable and durable — at least, much more so that the others.

    However, while a two week supply of water is a great starting point, it’s just that — a starting point. The common counsel for food storage is three months (for a variety of reasons; in one scenario, having to quarantine at home because of a flu pandemic would likely be two to three months), which means that you need three months of water storage to go along w/ that food.

    So a two week water storage supply should never be treated as “I’m done!”, but instead only as a minimum short-term supply. Long-term water storage is a crucial component of overall emergency preparedness.

  • I was wondering if I buy my water at the local water store here in town and keep rotating it to always have a 2 weeks supply since its only 25 cents a gallon do I still need to worry about this?

    My thoughts on this:

    In the water PDF linked above, I talk briefly about some of the plastics used for common water bottles you can get from the store. Whatever you do, don’t get the kid that are shaped like milk jugs. Avoid them like the plague.

    I like the sturdy Arrowhead kind of bottles since they’re stackable and durable — at least, much more so that the others.

    However, while a two week supply of water is a great starting point, it’s just that — a starting point. The common counsel for food storage is three months (for a variety of reasons; in one scenario, having to quarantine at home because of a flu pandemic would likely be two to three months), which means that you need three months of water storage to go along w/ that food.

    So a two week water storage supply should never be treated as “I’m done!”, but instead only as a minimum short-term supply. Long-term water storage is a crucial component of overall emergency preparedness.

  • Tara

    I was wondering if I buy my water at the local water store here in town and keep rotating it to always have a 2 weeks supply since its only 25 cents a gallon do I still need to worry about this?

  • Tara

    I was wondering if I buy my water at the local water store here in town and keep rotating it to always have a 2 weeks supply since its only 25 cents a gallon do I still need to worry about this?

  • Grannie K

    I just found your site about a week ago. You do a great job!! I like the water information. I especially like the “baby steps” approach. I never could make myself go into debt a couple of thousand dollars for food storage I didn’t know if I would even eat. Doing it a little at a time and getting things I will use and that you show us how to use is wonderful. I don’t quite have a year’s supply yet, but I’m getting closer all the time and I do try hard to rotate all my stuff. Thanks for all you efforts and the time you spend sharing with all of us.

  • Grannie K

    I just found your site about a week ago. You do a great job!! I like the water information. I especially like the “baby steps” approach. I never could make myself go into debt a couple of thousand dollars for food storage I didn’t know if I would even eat. Doing it a little at a time and getting things I will use and that you show us how to use is wonderful. I don’t quite have a year’s supply yet, but I’m getting closer all the time and I do try hard to rotate all my stuff. Thanks for all you efforts and the time you spend sharing with all of us.

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  • In the opening of my previous comment where I said “When it comes to…” I meant to say “purifying” rather than “filtering”, since filtering (like treating) is only one component of overall water purification. Minor detail, but I don’t want to confuse anybody!

  • In the opening of my previous comment where I said “When it comes to…” I meant to say “purifying” rather than “filtering”, since filtering (like treating) is only one component of overall water purification. Minor detail, but I don’t want to confuse anybody!

  • Jodi

    Thanks for the tips on the water filters guys. We’ll have to look into these options. I had read in several places that filtered water is not as good as the other purification methods so i didn’t research into filters too deeply. We will do some more research and update our post with our recommendations.

  • Jodi

    Thanks for the tips on the water filters guys. We’ll have to look into these options. I had read in several places that filtered water is not as good as the other purification methods so i didn’t research into filters too deeply. We will do some more research and update our post with our recommendations.

  • Connor

    When it comes to filtering water, more is better! I always recommend that people “double up”, in that they treat and filter water that is used in long-term storage scenarios. This ensures the removal of particles, bacteria, virii, scary-sounding microorganisms, and all the rest. (Provided, of course, that you have a good filter and treatment plan.)

    Personally, I have an AquaRain filter (comparable in many ways to the Berkeys) as well as a few treatment options to choose from, depending on the volume of water I’m needing to treat. As was indicated in the post, most municipal water is pre-chlorinated, though if it’s been stored for a couple years you will still want to treat it.

    Keep in mind that long-term water storage is VERY important. I’ve documented several options in the PDF I created (linked above under “additional resources”), so you can choose what works best for you. But while we all tend to think primarily about food storage, 95% of the food we store requires water to cook/use it, not to mention the need for water in terms of hygiene, hydration, and sanitation. Few people worry about water, thinking that they’ll be able to collect rain or get some from a nearby river. But this same mentality is what prevents people from storing food (thinking that they’ll always have access to a grocery store or the Mormon neighbor down the road who has a year supply). We need to store water for long-term situations, and more importantly, know how to use it.

    There are a bunch of combinations you can use for making sure your stored water is ready to use, but again, I stress the importance of both filtering and treating your water. Bleach works great in many situations, but doesn’t get 100% of what’s in there. For this reason I always advocate both a treatment and filtration option to be sure that the water we drink is helping and not hurting us, especially in a situation where having health and strength would be most needed.

    My 2¢.

  • Connor

    When it comes to filtering water, more is better! I always recommend that people “double up”, in that they treat and filter water that is used in long-term storage scenarios. This ensures the removal of particles, bacteria, virii, scary-sounding microorganisms, and all the rest. (Provided, of course, that you have a good filter and treatment plan.)

    Personally, I have an AquaRain filter (comparable in many ways to the Berkeys) as well as a few treatment options to choose from, depending on the volume of water I’m needing to treat. As was indicated in the post, most municipal water is pre-chlorinated, though if it’s been stored for a couple years you will still want to treat it.

    Keep in mind that long-term water storage is VERY important. I’ve documented several options in the PDF I created (linked above under “additional resources”), so you can choose what works best for you. But while we all tend to think primarily about food storage, 95% of the food we store requires water to cook/use it, not to mention the need for water in terms of hygiene, hydration, and sanitation. Few people worry about water, thinking that they’ll be able to collect rain or get some from a nearby river. But this same mentality is what prevents people from storing food (thinking that they’ll always have access to a grocery store or the Mormon neighbor down the road who has a year supply). We need to store water for long-term situations, and more importantly, know how to use it.

    There are a bunch of combinations you can use for making sure your stored water is ready to use, but again, I stress the importance of both filtering and treating your water. Bleach works great in many situations, but doesn’t get 100% of what’s in there. For this reason I always advocate both a treatment and filtration option to be sure that the water we drink is helping and not hurting us, especially in a situation where having health and strength would be most needed.

    My 2¢.

  • Ruth

    This is an awesome award-winning portable water-purifier that we keep in our 72-hour backpack kit. It is small and weighs less than 1 pound. It is amazing when you research all that it removes from water. I recommend that people check it out:
    http://www.amazon.com/First-Need-Deluxe-Water-Purifier/dp/B0009RP8T2/ref=pd_bbs_sr_1?ie=UTF8&s=sporting-goods&qid=1232032109&sr=8-1

  • Ruth

    This is an awesome award-winning portable water-purifier that we keep in our 72-hour backpack kit. It is small and weighs less than 1 pound. It is amazing when you research all that it removes from water. I recommend that people check it out:
    http://www.amazon.com/First-Need-Deluxe-Water-Purifier/dp/B0009RP8T2/ref=pd_bbs_sr_1?ie=UTF8&s=sporting-goods&qid=1232032109&sr=8-1

  • CTDaffodil

    Loving your site!!
    Although I’m on the other side of the country and not an LDS member – I really enjoy the work you all put into your site. I looked at the Macey’s ad for this week – what fantastic deals!
    Thanks for the water purification tips – all preparedness info is valuable

  • CTDaffodil

    Loving your site!!
    Although I’m on the other side of the country and not an LDS member – I really enjoy the work you all put into your site. I looked at the Macey’s ad for this week – what fantastic deals!
    Thanks for the water purification tips – all preparedness info is valuable

  • Some “water filters” remove germs and parasite eggs. I like the Berkey Water filters. You can see them at http://www.berkeyfilters.com Here is a quote from their site:
    “The Berkey water filter system is so revolutionary that it removes pathogenic bacteria, cysts and parasites to non detectable levels, removes harmful or unwanted chemicals to below detectable levels, and reduces nitrates, nitrites and unhealthy minerals such as lead and mercury without removing the healthful and nutritional minerals that your body needs.”

    A friend of mine already has one and loves it. We plan on getting one this spring. The filters don’t need replacing when dirty, just rinse them in clean water and keep right on using them. I think this is better to have on hand so that I can save what fuel I have in an emergency for cooking and heat, not purifying my water. Just a thought! Thanks for a great site!

  • Some “water filters” remove germs and parasite eggs. I like the Berkey Water filters. You can see them at http://www.berkeyfilters.com Here is a quote from their site:
    “The Berkey water filter system is so revolutionary that it removes pathogenic bacteria, cysts and parasites to non detectable levels, removes harmful or unwanted chemicals to below detectable levels, and reduces nitrates, nitrites and unhealthy minerals such as lead and mercury without removing the healthful and nutritional minerals that your body needs.”

    A friend of mine already has one and loves it. We plan on getting one this spring. The filters don’t need replacing when dirty, just rinse them in clean water and keep right on using them. I think this is better to have on hand so that I can save what fuel I have in an emergency for cooking and heat, not purifying my water. Just a thought! Thanks for a great site!