How Much Bleach to Store

I’m a numbers sort of gal, and this week I was pondering how much bleach I should really be storing for an emergency. Water purification –  As always, I should mention that boiling is best. But, boiling takes time, it takes fuel and sometimes that might not be available or prudent. Yes, you can get chlorine designed for pools and use that, but I don’t have a pool, and finding cheap pool supplies isn’t as easy out here in rural Iowa as it might be for some of you. Bleach however is widely available, in large, strong, storage ready containers. Numbers –  3 gallons of water per person per day.  I store for 5 now (4 humans, 1 cat). That works out to 15 gallons of water per day.  Yes, yes, most sites tell you to store 1 gallon per person per day, but really, have you ever tried to stay hydrated and clean with only 1 gallon of water for a day? It’s really hard. And after a disaster, cleanliness becomes more important, not less, 3 is as low as I’ll go for my estimates. One gallon of Clorox bleach will, on average, sanitize 3000 gallons of water (less if the water is particularly dirty). So, 3000/15 gives me 200 days of water for each gallon of bleach.  That’s not bad.  That’s actually a lot better than I thought.  Of course, it helps that I’m not watering livestock and my family size is small.  If I’m only planning for my family, all I’d need to store is 2 full gallons of bleach to assure a whole years worth of sanitized water.  That’s super cheap insurance. Now, let’s look at some other factors.  Do you have livestock that will need clean water? From a small flock of chickens all the way up to a dairy cow, if you know you’ll be providing water for animals, and if you want to insure their water is free of bacteria/viruses/staph/flu/e-coli, bleach might be a better solution than boiling.  Chickens might need only a gallon of bleach a year for their water sanitizing needs, but cows need 25 to 50 gallons of water per day, so you’re looking at 60 days of water sanitizing for one cow with each gallon of bleach. How long until your neighbors run out? Assume they have less than one gallon of bleach in their house, we’ll say 1/2 gallon to make the math easy.  That means your average suburban neighbor will have 100 days worth of water sanitizing bleach, before they have to rely solely on boiling, or begging some from more prepared neighbors. Again, that’s better than what I thought I would find after running numbers.  Now, whether or not they’ll have the knowledge to use it properly, I won’t even speculate on. Does anyone else notice how often random comments to a boil order shine a light on the ill-prepared? Something to the effect of  “How can we boil water with no power?!” It’s a classic, makes me giggle/cry every time.
Ratio of Clorox Bleach to Water for Purification FILTER first to remove particulates. 2 drops of Regular Clorox Bleach per quart of water 8 drops of Regular Clorox Bleach per gallon of water 1/2 teaspoon Regular Clorox Bleach per five gallons of water If water is cloudy, double the recommended dosages
Filters have their place, especially the really nice ones like Berkeys, but in terms of cost, nothing beats bleach. – Calamity Jane
30 comments… add one
  • ar/charlie February 9, 2012, 8:17 am

    I have 3 @ 5000 gal dark green plastic water tanks (in shaded area)
    how can I keep these full with good water for long term storage…..
    can I santize them when I am ready to use…???

  • TexasMushroom February 9, 2012, 9:28 am

    When I first started prepping, I stored 4 gallons of chlorox in a small closet away from food. After about 3 years they all developed pinholes in the plastic jugs and leaked. Where each jug leaked, the bleach ate through the wood floor leaving a 1-3 inch hole. Now with 3-4 jugs, I rotate one jug each year and keep a much closer eye on the condition of the jugs.

    • Stoosh February 10, 2012, 5:57 pm

      I actually keep my bleach jugs in the bathtub and leave the drain open (unplugged). If they ever leak, the bleach will flow down the pipe. No muss, no fuss. Of course, when bathtime comes, I remove the jugs!

    • Post Apocalypse February 12, 2012, 12:43 pm

      That is excellent advice because I have 3 bottles of clorox stored in a closet that I have completely forgotten about but they have only been there for a year or so. I did not take into account the fact that they would eventually eat through the plastic.

      Do you know if the same plastic material is used now or have any ideas on other ways to store the bleach?

  • Presager Buddy February 9, 2012, 9:28 am

    I consider your two gallons of bleach for one family about what I’ve calculated for myself and my family. It might be noted that bleach loses its effectiveness over time. Storing more than you need and using it in rotation means alway using bleach that has lost its full strength.

  • Joe February 9, 2012, 10:00 am

    Dry chlorine is the answer! Aka Pool Shock. Also known as calcium hypochlorite, it is used primarily in swimming pools. Since it is a powder, it has the significant benefit of extended shelf life. Dry chlorine may be stored for up to 10 years with minimal degradation if it is kept dry, cool and in an airtight container.
    This is a far better choice for quantity storage than liquid bleach. Dry chlorine is commonly available at swimming pool supply stores as well as many hardware and grocery stores.
    For chlorinating water in rain tanks, the recommended dosage is seven grams dry (1/4 ounce by weight) or 40 milliliters (1.35 ounce) per 1000 liters (264 gallons). Let the water stand for 24 hours before drinking. To maintain chlorination, add one gram (.035 ounce) of dry chlorine or 4 ml (.135 ounce) weekly per 1,000 liters.

  • Walt February 9, 2012, 10:51 am

  • Barbie February 9, 2012, 11:25 am

    This is a great post, especially the info about how much water to store per person. I had no idea that liquid bleach would eat through its own bottle eventually either!

  • laura bradley February 9, 2012, 11:32 am

    Just a thought here…while its ‘safe’ to drink please keep in mind that bleach, no matter how small the amount, will harm PLANTS, GRASS, ETC…so if you use bleach water to clean after a SHTF situation, dump the water where you aren’t trying to grow anything…even in minute amounts, over time, it will KILL the plant…been there done that.

    • Presager Buddy February 9, 2012, 12:57 pm

      Indeed, a water/clorox mix is an inexpensive way to kill poison ivy.

      • Michael February 9, 2012, 1:29 pm

        Thanks for the reminder. I can totally see myself doing that, even though I know better.

  • Veridical Driver February 9, 2012, 1:18 pm

    +1 for Pool Shock. Cheaper, lasts longer, and is space efficient. When you store bleach, you are storing mostly water.

  • Michael February 9, 2012, 1:35 pm

    I don’t store much bleach at all. I have a quart in the laundry room and when it gets half empty, I’ll go buy another quart. That’s enough to serve my needs.

    Aren’t you out in the country and on a well? Bleach seems more like something you’d worry about if you were worried about a long term collapse and you were on city water.

  • Satori February 9, 2012, 2:22 pm

    if you use “pool shock”
    make ABSOLUTELY sure there are no other chemicals
    such as algaecides in it

    • Presager Buddy February 9, 2012, 4:33 pm

      Very good advice. Also, personal safety equipment should be worn when handling this stuff (goggles, gloves, etc.)

  • the old guy February 9, 2012, 5:30 pm

    Hey, why use poison? Look up info on FOOD GRADE hydrogen peroxide. Check it out at For another helpfull and fascinating read, check out The farmshow magazine. Good Prepping!

  • KC February 9, 2012, 8:37 pm

    Calcium Hypochlorite isn’t as difficult to obtain as it would seem. Most preparedness vendors and industrial supplier vendors have it in stock and will ship depending on where the destination address is located. However like small arms ammunition, there is a HAZMAT fee associated with the shipping, which is normally in addition to standard shipping. This being said, the Calcium Hypochlorite is far superior to liquid bleach for long-term storage. Provided that one has a vacuum sealer, one could by all rights, store smaller pre-measured quantities of Calcium Hypochlorite for ready use, instead of opening the jar, doling out the desired quantity, and resealing the jar, which depending on climate would reduce the effective shelf life of the Calcium Hypochlorite. Just a tip from a jerk who used the stuff, for a long time down-range.

  • Jason February 9, 2012, 9:40 pm

    Boy oh boy Jane, you’ve got it all wrong! Didn’t you learn anything from your experience in India? A family of 5 can survive easily on a gallon of water a week. If you include bathing, add another gallon.

    Sheesh, how spoiled are we here in the states?


    Don’t worry, I won’t quit my day job!

  • T.R. February 9, 2012, 9:53 pm

    I would say more than you think you need rather than less . Bleach has too many uses to be skimped on . Purification , sanitation , not to mention used for its intended purpose as well . Vinegar is another multi purpose item not to short yourself on .

    • Jason February 10, 2012, 10:00 am

      Vinegar is awesome & has many uses – I drink Braggs unfiltered apple cider vinegar mixed with water everyday for the heath benefits.

      • T.R. February 11, 2012, 12:39 am

        I also get the Italian balsamic vinegar once in awhile , good for sipping , goes good with loose leaf chewing tobacco ;)

  • Richard H February 9, 2012, 10:51 pm

    One topic I rarely hear discussed is the aquistions of water. By that I mean getting your hands on any water at all. You might be fine out in the sticks or some other semi-rural area but in a suburb or city where do you go once the water stops flowing from the tap? Bleach is good for sanitizing bad water but you still nedd water. I recommend storing as much water as possible in addition to finding a secondary source of water. A lake, pond, or well would be more than adequat.

    • T.R. February 13, 2012, 8:32 pm

      Thats a good point , that gas syphon we have might be , and most probably will be better used for getting water .

  • Northernhomesteader February 10, 2012, 1:51 am

    Great post, thanks for sharing your thoughts on uses for bleach. I concur with above comments as well that vinegar is important to have on hand. Colloidal silver also, for treating cuts and infections, etc.

  • JC Refuge February 10, 2012, 12:44 pm

    Sorry–this post is completely untrue and dangerously misleading. Bleach does indeed have a shelf life. It is anywhere from 6-12 months.

    Have a look here from the Clorox site:

    It actually degrades quite quickly, even if you never open a bottle, and it is susceptible to storage conditions. Not a good choice to have laying around in large quantities for other reasons as well, since it can be very poisonous in liquid and gaseous form.

  • JayJay February 10, 2012, 3:58 pm

    Nothing beats bleach, BUT–and there is one–bleach I’m told only stores for about 5 months and then loses its potency.
    I store pool shock–calcium hypochlorite; one bag is cheap, available, and goes a long way, like thousands of gallons.
    Now, for those storing bleach, and rotating, as I know you are, please remember to store Tang and other instant drink mixes to battle the chlorine taste if needed.
    I have lots of Tang, Countrytime, instant tea, instant coffee, and koolaid on my shelves.

  • petar February 10, 2012, 4:53 pm

    I would add the following:
    Chlorine dioxide is selective for the things it kills and that is the reason it kills pathogens and doesn’t harm the body. Here is a quote by the US Gov EPA:

    4.1 Chlorine Dioxide Chemistry: Chlorine dioxide functions as a highly selective oxidant due to its unique, one-electron transfer mechanism where it is reduced to chlorite (ClO2) (Hoehn et al, 1996).

  • Pangea February 10, 2012, 6:05 pm

    Clorox has a shelf life that is relatively short if what I hear about it is true. Dry Calcium Hypochlorite, also known as Pool Shock lasts forever on the shelf and a small pack will treat many thousand gallons of water.

    • Jason February 15, 2012, 1:44 pm

      That is totally true – great tip!

  • john burns March 5, 2017, 4:58 pm

    yes pool shock is great. a little goes a long way for water purification. there are some gov info on this under field biological agent decon methods. takes awhile to find but good stuff. also Walmart has little tabs of dry bleach in the laundry section. Also city folks….your hot water heater has a bunch of stranded water in it in a pinch. make sure the drain valve works each year, which should be a part of home maint.


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