Jodie Weston
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If I were to ask how many of you store liquid bleach along with your other prepping supplies, I am certain that a good percentage of you would raise your hands. Liquid bleach is a powerful disinfectant and sanitizer but did you know that there is something better? Something with an almost indefinite shelf life that is inexpensive and takes almost no room to store?
That something is the chemical Calcium Hypochlorite most commonly known as Pool Shock.
I have known about Pool Shock for years but because it is not readily available in my area, I never took the time to search it out so I could stockpile some for my own emergency preps. That has now changed and today I plan to show you how to use Pool Shock the easy way, step by step.
Why Not Bleach?
Before we start, you may be asking “why not use liquid chlorine bleach?”. There are a few problems with liquid household bleach. It takes a lot of room to store bleach plus the usable shelf life is only six months to a year depending on storage conditions.
The folks at Clorox say this:
The active ingredient in liquid bleach, sodium hypochlorite, is very sensitive to high heat and freezing, but under normal home storage conditions, it should still perform well for nine to twelve months.
In addition to limited shelf life, there is another problem. I have had reports from Backdoor Survival readers telling me that in their area, they can only purchase “Clorox Ultra” which is concentrated. When I called Clorox to ask how to use concentrated bleach to purify water, they said that it was not intended to be used in that manner and why would I want to do that anyway. Seriously, their representative actually said that.
Pool Shock – The Boilerplate
When I started doing research for this article, I visited some of the most respected survival and preparedness blogs and forums for background material. After all, pool shock is pool shock and there must be some standards for use, right?
With just one exception, all of the sites I visited included this boilerplate from the EPA:
You can use granular calcium hypochlorite to disinfect water.
Add and dissolve one heaping teaspoon of high-test granular calcium hypochlorite (approximately ¼ ounce) for each two gallons of water, or 5 milliliters (approximately 7 grams) per 7.5 liters of water.
The mixture will produce a stock chlorine solution of approximately 500 milligrams per liter, since the calcium hypochlorite has available chlorine equal to 70 percent of its weight.
To disinfect water, add the chlorine solution in the ratio of one part of chlorine solution to each 100 parts of water to be treated. This is roughly equal to adding 1 pint (16 ounces) of stock chlorine to each 12.5 gallons of water or (approximately ½ liter to 50 liters of water) to be disinfected.
To remove any objectionable chlorine odor, aerate the disinfected water by pouring it back and forth from one clean container to another.
Have your eyes glazed over yet? Mine have. Being an accountant, I like to deal in absolutes so what is this business about “one heaping teaspoon”? Plus, what’s up with the references to “approximately” and “roughly”?
I decided that it was time to do my own testing, and sure enough, each time I measured out a heaping teaspoon, I had different results; they ran the gamut from 1 1/4 teaspoons to 2 teaspoons. This made my head hurt.
Another thing. Over and over I read that you should use pool shock that is a minimum of 78% calcium hypochlorite with the balance being inert ingredients. Fair enough, but there are two problems with this. First, what you find locally maybe 68%, it may be 78%, or it may be something else. Second, the EPA makes no such recommendation or at least none that I could find. They simply say “high-test”.
Did I mention this made my head hurt?
But there is more. I actually found a couple of sites that said to use one heaping tablespoon of Pool Shock for every two gallons of water! You know, just because you find something on the internet does not mean it is true.
My conclusion? The exact amount and the exact percentage does not matter as long as it is within a reasonable range and close to the EPA standard. I do think it is important that the pool shock does not contain other additives that may or may not be safe even when highly diluted. Other than that, however, it is my belief that the precise percentage of Calcium Hypochlorite to inert ingredients does not matter as long as it is 68% or higher.
For my own use, I settled on 1 teaspoon of pool shock per gallon of water when making up my stock chlorine solution. Then, to disinfect water, I used 3/4 ounce of my pool shock solution to treat a gallon of water. This makes it easy to calculate how much to use for water disinfection, regardless of the size of your container.
Step-by-Step: How to Purify Water Using Pool Shock
The first thing I did was to gather my supplies. Notice that I used eye protection goggles and rubber gloves. Other supplies included an empty bleach bottle, funnel, shot glass, and measuring spoons.
I verified the size of my stock chlorine solution container, namely a repurposed bleach bottle. My bottle held 1.42 gallons and I wrote this on the outside with a Sharpie pen. My intent, however, was to only prepare 1 gallon of stock solution to keep the math simple.
After donning my protection gear, I added water to my stock solution bottle, carefully measuring the quantity. I used exactly one gallon of water.
I then measured out some pool shock; one level teaspoon to be exact. I put the cap back on the bottle and swished it around a bit. I gave it a sniff test and it definitely smelled bleach-like.
The next step was to purify water. I wanted to make drinking water and for me, the smaller the jug the better. I chose a 64 ounce repurposed apple juice jug. Remember the easy math? The EPA says 1 part chlorine solution to 100 parts water so the math is 64/100 = .64 ounces.
Keeping things easy, that translates into approximately 2/3rd ounce. Remember, the EPA guideline uses the word “approximately” all over the place. That was good enough for me. To easily measure the proper dilution, I used a mini shot glass that had measurement markings along the side.
Be sure to pour your pool shock into your water and not the other way around. The last thing you want is to splash the solution on yourself on the surrounding surfaces (although you have probably noticed that I did this outdoors).
After preparing my newly purified drinking water, I drank up. Three things. I did not throw up, I did not get diarrhea and I did not get sick or die.
I am comfortable with the results even though the solution I made may have been slightly stronger than the EPA guidelines. Then again, given the vagueness of the EPA guidelines, perhaps my measurements were spot on.
Note: I did not find that my water had an objectionable smell or taste. True, it was not sweet tasting like the water coming out of my Royal Berkey but it was palatable. If your own purified water has an unpleasant odor, simply aerate it by pouring it back and forth between clean containers. This trick applies to any water, not just water treated with pool shock.
Label your pool shock solution. This is powerful stuff. Get out your Sharpie and label the jug with as much information as you can. Store it, in the same manner, you store liquid bleach, up high and away from pets and children and in a location that is cool, dark and dry.
Also, store your unused pool shock safely. Because it is corrosive, I chose a mason jar with a plastic lid. Plus, rather than empty the pool shock into the jar, I sealed the plastic bag it came in with a clip and stuffed the bag inside of the jar.
Other Handling and Storage Considerations
I contacted the manufacturer of the pool shock I purchased and requested a Material Safety Data Sheet on the product. They promptly responded and here is what it said about handling and storage:
Keep product tightly sealed in original containers. Store product in a cool, dry, well-ventilated area. Store away from combustible or flammable products. Keep product packaging clean and free of all contamination, including, e.g. other pool treatment products, acids, organic materials, nitrogen-containing compounds, dry powder fire extinguishers (containing mono-ammonium phosphate), oxidizers, all corrosive liquids, flammable or combustible materials, etc.
Do not store product where the average daily temperature exceeds 95° F. Storage above this temperature may result in rapid decomposition, evolution of chlorine gas and heat sufficient to ignite combustible products.
Recommendations
Now that I have been through the process and understand the math, I am comfortable using pool shock to purify water for drinking, hygiene, and sanitation purposes. It is not, however, an excuse for not storing water nor an excuse for not having a supply of traditional water purification liquids or tabs that are pre-measured and simple to carry with you in bug-out-bags and emergency kits.
As far as I am concerned, the pool shock I have purchased is reserved for dire emergency use, period. Yes, I feel it is safe, but it is still a powerful chemical solution as is liquid bleach. I will use it as the water purification method of last resort and if the time comes, I will be thankful I have it on hand.
Disclaimer
I have to say this: I am not a chemist and I am not an expert. My methods are my own and they work for me. That being said, if you have any hesitation at all, visit other resources including the EPA and make the decision to use pool shock your own and not just something someone told you to do. Here is a link: Emergency Disinfection of Drinking Water.
The Final Word
Everywhere you look you will see a recommendation to store bleach for water purification. I have made that recommendation and so have many, if not most, of my blogging peers. What you may not have seen is that liquid bleach has a limited shelf life of 6 to 12 months. I fear that this could be leaving a lot of people ill-prepared to produce safe, potable water in an emergency.
This means that a person that began prepping a year ago, and does not know to rotate their bleach, is already living with false security when it comes to water purification. And what about people that have been prepping longer?
As long as pool shock is stored properly, it will have an almost indefinite shelf life plus, a small one-pound package will treat many thousands of gallons of water. Ten thousand to be exact. It can be mixed and used as potable water and as a disinfectant, just like bottled liquid bleach. So if you have a water storage tank and need something for emergency water disinfection, a hypochlorite solution could work out well for you.
At the end of the day, do your own research and decide for yourself.
Enjoy your next adventure through common sense and thoughtful preparation!
Gaye
88 Responses to “How to Use Pool Shock to Purify Water”
So the pool shock is granular. Instead of formulas how to mix up basically a bottle of chlorine, would you be able to convert to say 10 granuals of pool shock per 16 oz glass of water so you don’t have to make up a large quantity to carry around? It would be great to just dump a certain number of granuals straight into your drinking container. The question is, how many granuals per ounce?
Pool Shock is a powerful and potentially toxic chemical if not used properly. Also, it is powder-like and would be difficult to measure on a grain by grain basis.
I have a 30,000 gal swimming pool. I have always thought of this as my water back up plan. I keep 30 days worth of bottled water on hand. Collect rain water off my roof. Does anyone know the best way to change swimming pool water into drinking water? The pool water has chlorine, acid and clarifiers in it. Just my luck I would probably need the water just after I’ve shocked the pool.
I am checking into this for you. The last thing I want to do is pass on bad information. Of course, eventually the chlorine would dissipate on its own, but still…
I am pretty sure the SolarBag from Puralytics will work although it does seem counter-intuitive. //www.backdoorsurvival.com/solarbag-water-purifier/.
I would recommend NOT using pool water for long term drinking purposes. Many of the chemicals such as algecides used to keep the water clear are not safe for general human consumption. Nothing short of distilling the water will remove those chemicals.
In addition, sunlight denatures the chlorine. Even covered with a tarp, within a week your pool’s chlorine levels will be at 0. And while you might have spare chlorine on hand to continue to mix, if you have no electric power to run the pumps, filtration, and agitation then its effectiveness will be diminished because it is not dispersed adequately throughout the pool.
And finally, studies by the CDC indicate that over half the pools in Atlanta contain E coli. Although the study was conducted in Atlanta, there is no reason to believe that the study would not be consistent throughout the US. //www.usatoday.com/story/news/nation/2013/05/16/pool-water-feces/2166195/
In essence, within just a short time, water within pools could and should be considered questionable. The risks skyrocket if it is not a pool that you personally treated. So if your pool is your long term water solution, think again.
Thanks for the helpful information…Any guidelines for using this as a “wipe-down” disinfectant? BB
Just wondering if you ran the water you purified through your Berkey water system and if there would be a reason not to do that. I would assume that it would improve the taste, but not that familiar with the Berkey products to know if the water you purified with the Pool Shock would some how contaminate it.
I had wondered the same thing as I was writing the part about “not as sweet tasting” as the Berkey. I don’t see why not, though, since all we are doing is creating chlorinated water. Naturally, we do not want to ruin our Berkey filters so I do plan on getting a definitive answer.
I have a shelf lined with ‘instants’–Tang, tea, fruit drinks, Country Time, even Koolaid!!!—lots of these to kill the bleach taste if there is one.
Good luck and God bless.
I treat my cistern on a regular basis with the pool shock. I run the drinking water through the Berkey and the water is wonderful. It tastes like spring water.
It is always an estimate how much shock to use. It depends on what is in the water, mud, leaves, larvae etc. (I also have pool.) You want to smell strong chlorine after treating the water. The smell will dissipate.
Buy a pool test kit that has chlorine, PH and alkalinity testing. When you finish treating with shock, you want the reading to be off the chart with the chlorine and let it come down on its own.
The politest kit is good to establish a base line but when the pool test kit shelf life runs out you will always have your nose to determine if it is enough. The reason they call it pool shock is that you must out enough in to kill all – which is a shock to that system.
It is great that someone is using pool shock in a way I could only project to using it after the SHTF.
Thanks,
Thank you Gaye for the point blank article with the bits of humor in it. I too have found so many articles that are all over the place and not to clear or conclusive with their information. A couple of suggestions. You should wear a face mask while mixing this chemical and outside is best; avoid making in damp conditions. Also there should be a waiting time between treating the water and drinking it.(I know you know this but the article didn’t state this)
Question: Once the water has been purified and some time has passed like 20 min. does the bleach in the water become inert?
This article I read //readynutrition.com/resources/better-than-bleach-use-calcium-hypochlorite-to-disinfect-water_19062010/ is one that is all over the place, it is the responders that have some good information (and some bad information) that I found informative. One gentleman gave the information on the ‘other additives’
‘OTHER’ ingrediants in calciumhypochlorite, ‘pool shock’. As with any list of ingrediants(food or food) the first ingrediant is your largest amount. So here goes.
First is chlorine; your active ingrediant 47>76%. Next is your OTHER ingrediants; sodium chloride (plan salt) 10>20%; cal.chlorate 0>5%; cal.chloride 0>5% (used in beer brewing, flavering pickles, A firming agent for turning soybean curd into tofu——). cal.hydroxide 0>4%; (also called slaked or pickling lime). cal.carbonate 0>4% (think of Tums/antacids).
One last thing.Check Ph after treating. needs to be 7.2>7.6
Another not so gentlemanly “Mark” gave a response to Christopher’s information. But “Mark” had sound advise on the dangers of storing calcium hypochlorite. (People need to be nice in responding to people’s lack of knowledge or ignorance)
I am not sure you would call it inert, the Chlorine vapors off. The Chloring doesn’t want to stay in the water and will convert to a free gas if given the opportunity. Similar to CO2 in soda.
Thank you so much gaye.. You know we have used this for years as a laundry bleach ( one tablespoon per load) and have heard that is could be used to disinfect water but every time I read something new the amounts used was different.
We all needed to know this Gaye. Thanks. I’m like JimW. How does your stock solution compare in strenth to my bottled bleach? For long term water storage, I have always poured liquid bleach into my storage container, swished it all around, then poured it out. I then added my water. This is suppose to add the correct amount of bleach to your container to hold down nasties while in storage. Could your stock solution be used in the same way?
Why not simply add some pool shock solution and store it that way? That would be easy enough and a no-brainer. Basically, you would be using the pool shock as a bit of insurance against nasties that may (or may not) develop while the water is in storage.
For example, I used an Aquimira purification liquid when I filled my 55 gallon water barrels. I could have used the calcium hypochlorite stock solution instead. The math? 55 gallons/100 = .55 gallons of pool shock. It could be done.
For me, the most important aspect of this article was figuring out the math so that I could create drinkable water on the fly. That plus, as always, skill building via practice.
Pool Shock when mixed with water lasts no longer than bleach in a bottle.
I plan to mix only what I need in a 2 liter bottle with the directions below.
As a chemist, JayJay is right. You showed storing the stock solution and it will get progressively weaker over time. After mixing the stock solution with your water to be purified, Immediately after adding the stock solution, smell the water and make sure you can smell chlorine in it. You have to let it sit for 20-30 minutes for the chlorine to kill any target micro-organisms, then it is safe to drink. Just pour the water back and forth between two containers to remove any residual chlorine smell/taste. (It is displaced by air as it is poured.) Thank you for a very well thought out and through show and tell.
Also, colloidal silver (CS) can be used in the washer to disinfect and clean clothes. I wash my hair with it and it keeps it clean much longer than normal. I can’t think of anything CS can’t improve.
I use undiluted colloidal silver to purify water. No odor, it works, it’s easy…just pour some in, and it’s good for us. Spraying and letting it set on counters, etc. for 10 min. disinfects them. Spraying it on food makes it last longer. Drinking it keeps us healthy…very inexpensive if you make your own. There are dozens of uses for it and it’s always SAFE.
Using colloidal silver is on my bucket list of projects. Like the use of calcium hypochlorite (pool shock), some of the instructions and dilutions I read make my head spin. I want to break it down into simpler terms.
I know you have sent me information in the past; I need to dig it out and read it again. If I need some help, I will let you know.
Gaye, when you go to make CS you may want to get a TDS meter, if you don’t already have one. Amazon has one for around $10.
(TDS = Total Dissolved Solids) – it does not say what the solids are, but if you start with distilled water it reads 00.0, so any reading on the meter would be what you put in it (silver for colloidal silver). Reading is generally in parts per million.
under 50 ppm – ideal drinking water
approximately 350 ppm – average tap water in America (mine shows 34 ppm)
If TDS levels exceed 1000 ppm, however, it is generally considered harmful to human health and should not be consumed.
(data from tdsmeter.com)
This should also help checking how well your drinking water filter is working.
Thank you Gaye for getting a bunch of tangled up instructions straightened out! I will be writing these out, and probably be giving them a test run. One question, can the “stock” be used in the laundry room in place of normal liquid bleach or does it require more dilution?
I left out the part about use in the laundry because once again, I read conflicting information. What I do know is that cup per cup, the pool shock stock solution is much weaker than liquid bleach so logically, the quantity needed for a load of laundry would be huge if used in liquid form.
I do like Ken’s use of powdered calcium hypochlorite in the laundry though. That would be so much easier and safer to use than the liquid and would eliminate the fear of dripping the liquid on surrounding carpets. (My washer is in a small closet not a traditional utility room.)
I plan to get a test kit so I can measure the effectiveness of my pre-made stock solution over time. Does it become useless in a year? That would be good to know although my intended use would make it up fresh as needed.
The list of questions goes on so keep them coming. I plan to do some additional research.
Why not just buy a Big Burkey and some extra filters. Check with MFG, TO SEE IF THEY CAN BE SANTIZED WITH BLEACH or what ever and you can use water from creeks or rivers, farm ponds if not used to water cattle.
I do have a degree in chemistry and worked for a large swimming pool distributor. If you use Cal Hypo there is one VERY IMPORTANT thing to know (there are a few others too). It is an OXIDIZER!!! That is, it produces it own oxygen for combustion. You could put it in a vacuum and ignite it and it would still burn. You can’t put it out with a fire extinguisher or even 20 of them. Watched my warehouse guys handle some wrong one time and they went through 20+ extinguishers fast.
It reacts (ignites) with organic material (cigarettes, oil just about anything in your trash can) If you have to dispose of it dissolve it in water and pour the water in the toilet. Be careful with this product. It’s safe if you use it properly. It does not have a long shelf life 12-16 mos. tops. In St.Pete Fl a large distributor’s WH burnt to the ground because they miss-handled it.