Purifying water with Household Bleach

Discussion in 'General Preparedness Discussion' started by FreeNihilist, Feb 6, 2011.

  1. FreeNihilist

    FreeNihilist Well-Known Member

    Note: It is important to use plain old bleach without additives.

    Purifying Household Water

    The treatments described below work only in situations where the water is unsafe because of the presence of bacteria or viruses. If you suspect the water is unsafe because of chemicals, oils, poisonous substances, sewage or other contaminants, do not use the water for drinking.

    Storing water safely

    Store one gallon of water per person per day.

    Store at least a three-day supply of water per person.

    Collect the water from a safe supply.

    Thoroughly washed plastic containers such as soft drink bottles are best. You can also purchase food-grade plastic buckets or drums.

    Seal water containers tightly, label with date, and store in a cool, dark place.

    Replace water every six months.

    Never reuse a container that contained toxic materials such as pesticides, solvents, chemicals, oil or antifreeze.

    Water purification

    There are two primary ways to treat water: boiling and adding bleach. If tap water is unsafe because of water contamination (from floods, streams or lakes), boiling is the best method.

    Cloudy water should be filtered before boiling or adding bleach.

    Filter water using coffee filters, paper towels, cheese cloth or a cotton plug in a funnel.


    Boiling is the safest way to purify water.

    Bring the water to a rolling boil for one minute.

    Let the water cool before drinking.

    Purifying by adding liquid chlorine bleach

    If boiling is not possible, treat water by adding liquid household bleach, such as Clorox or Purex. Household bleach is typically between 5 percent and 6 percent chlorine. Avoid using bleaches that contain perfumes, dyes and other additives. Be sure to read the label.

    Place the water (filtered, if necessary) in a clean container. Add the amount of bleach according to the table below.

    Mix thoroughly and allow to stand for at least 30 minutes before using (60 minutes if the water is cloudy or very cold).


    Source: How to purify your drinking water

    It would be a good idea to print a few copies of this and laminate them and store them in a safe place such as a filing cabinet or with your supplies, so that you can reference the bleach ratios when needed.
  2. kolob

    kolob Member

    Great thread. I also store sodium hypochlorite powder like you would use in a swimming pool. If you have a water source you can make one heck of a lot of bleach with one 5 pound bottle.

  3. CulexPipiens

    CulexPipiens Still waiting for the zombies.

    This is a better approach. While the bleach works, the bleach itself is not a longer term solution... the powder is a LTS item and can then be used to mix up small quantities of bleach as needed. The manufacturers of bleach claim about a 6 month shelf life before it starts to degrade.
  4. FreeNihilist

    FreeNihilist Well-Known Member

    I should have noted that point, when I posted the article above. Yes bleach only has a 6 month shelf life when stored between approximately 50 and 70 degrees. Hotter temps such as tropical temps can cut this down to as low as 3 months. After this initial period of viability, a rate of 20% degradation occurs per year. Adjustments should be made for this when purifying water.

    However calcium hypochlorite which is what I assume, you guys are referencing and not a powdered sodium hypochlorite (bleach) has it's own pitfalls. It does indeed store longer due to being more stable but it also does degrade. As it degrades it release chlorine into the air as chlorine gas. A bottle of sodium hypochlorite does the same BUT the gas is contained within the bottle and exposure is very very limited. The calcium hypochlorite does not come in an airtight container after opening, to my knowledge. Proper storage precautions should be taken but seeing as calcium hypochlorite contains several times more chlorine, it releases several times more chlorine gas.

    Calcium hypochlorite does degrade but much slower, at a rate of around 5% per year versus around 20% per year after the initial fresh period of bleach (sodium hypochlorite solution). I feel safer using and storing bleach and adjusting for degradation as Im not going to be continously inhaling chlorine gas. Also calcium hypochlorite is unavailable in my area. This is the case for some areas of the US and world. Bleach however is very common.
  5. carolexan

    carolexan Junior Member

    Our son-in-law owns a pool service in Ft Worth. He brought us pool shock as it seems to have a long shelf life. I do keep a couple of cases of good old bleach handy.

    Thanks for posting this FreeNihilist as many newbies come everyday it's good to have some basics on water easy to find.
  6. lhalfcent

    lhalfcent Supporting Member

    It would be better and just as inexpensive to get Food Grade Hydrogen Peroxide.
    It works better with out the aftertaste of bleach.
    You have to dilute the peroxide which makes it so inexpensive!
  7. FreeNihilist

    FreeNihilist Well-Known Member

    Here's the issue with hydrogen peroxide. Its good for a year if the bottle is unopened and properly sealed but once you open it, its totally degraded and useless within 30 days. Also any contaminants such as dust, dirt, etc that could get into the bottle would compromise it's effectiveness.

    So sodium hypochlorite (bleach) is actually much more stable than hydrogen peroxide. That being said, calcium hypochlorite is more stable than sodium hypochlorite even.

    I also prefer Sodium Hypochlorite (Bleach) as it is what water treatment plants use actually. My body is already accustomed to it as well. So for me sodium hypochlorite ranks highest of all the methods Im familiar with.