While bleach is one of my least favorite water purification techniques, it has it’s place in emergency preparedness and is a very simple back-up for water purification. The important thing to know about bleach, however, is that you should not use it if you aren’t familiar with its application. People have killed themselves by adding too much bleach to their water. Hopefully this article educates you to a point that you don’t need to worry about that! Before we get started into the process I want to cover some pros and cons of using bleach to sterilize your water.
Pros
Easy
Inexpensive
Quick
Great for short term water purification
Cons
Bulky
Taste – Can be unappealing to some people
Ineffective for long term water storage
Temporary purification
Toxic when misused
Dangerous around children
Short shelf life
So now let’s get into the nitty gritty.
You can find bleach at any grocery store. Most household brands contain 5.25% sodium hypochlorite (NaOCL). In order to purify your water this percentage needs to be between 5% and 6% so most brands will work. If you are storing bleach for water purification be sure to get the pure original stuff. Nothing with added scents, colorings or chemicals. If it isn’t pure please, please, please don’t add it to your water!
Application
1 Gallon of Clear Water : 8 drops of Bleach
1 Gallon of Cloudy Water: 16 drops of Bleach
5 Gallons of Clear Water : 1/2 teaspoon of Bleach
5 Gallons of Cloudy Water: 1 teaspoon of Bleach
After adding the bleach, stir or shake the container. Allow the water to stand for 30 minutes. You should smell a slight chlorinated (pool water) odor. If you don’t smell this, add another dosage and wait another 15 minutes before drinking.
As you can imagine the water will have a slight chlorine taste to it. Another issue I have with Chlorine is it’s effectiveness and shelf life. The effectiveness of chlorine significantly drops after 6 months on the shelf. So in all reality you shouldn’t depend on your chlorine for purification if it is over 6 months old.
The other issue is it’s effectiveness. If you add chlorine to your water storage it won’t extend the shelf life of your water. Unless you are using 100% polycarbonite containers, your barrels will still leech into your water and you will still have to purify it when you use it.
So in summary, chlorine is one of my last resort water purification methods. It is very effective for temporary and quick purification. Your kids might not be too happy with the taste but if you have no other method this will work just fine. Safety first and happy prepping!
UPDATE: Based on some comments and emails I’ve received I’d like to address my concerns over leeching and bleach shelf life. My reply to a comment below: “Concerning both – I’ve found that emergency preparedness research is as saturated as the field of diet and exercise. One day we’re told not to eat salt, the next salt is okay. Then eggs are bad, then they’re okay. The research goes on and on without any statically conclusive results. Water storage is similar in regards to the fact that I have found mountains of research seeming to substantiate both the argument that leeching is a legitimate cause of concern and that it’s not. The same goes for the bleach efficiency. So considering that I have yet to be 100% convinced of the safety of leeching or the shelf life of bleach, I have chosen to post a cautious approach for the safety of my readers. I appreciate your comments however and welcome anyone and everyone to look into evidences against these two and make their own judgement as to its safety.”
Great article. I have a few questions, however. I’m not sure I understand how bleach’s efficacy decreases after 6 months. I am EXTREMELY skeptical of this statement. Do you have any reputable references for this?
Here is my reasoning:
A lot if not most bleach sits on the shelf for around 6 months before being purchased anyway.
I realize that there is a mechanism through which NaOCl decomposes to NaOH, Cl2 and O2 but I don’t think 6 months is quite enough for this to occur to any appreciable extent, especially in a sealed container (if this did occur quickly, for example, if you put bleach in an air-tight container it would eventually explode or the pressure would reduce the rate of decomposition so much that no more pressure would build up).
Anyway, if you don’t have a legitimate reference for this I would be very willing to test it and find out. It is a fairly simple test (which is why I’m pretty sure someone has done it before).
Jake, when I first heard this I was surprised as well. This is one site that I found that “broke it down” http://www.clorox.com/blogs/dr-laundry/2007/08/07/bleach-shelf-life/
Also, I think your concerns about leaching are just a little extreme.
As far as I know, bisphenol A is not used in the manufacture of HDPE but in polycarbonate. Even with polycarbonate, however, significant leaching only occurs at extreme temperatures (very hot water) and even then the levels are in the microgram per liter.
At room temperature the amount of bisphenol A leached from each gram of plastic (soaked in water at room temperature for 2 weeks) was 4.2 nanograms per gram. So, just for argument’s sake let’s say that the amount leached over 5 years is quadruple that (about 16 ng/g) and that the container weighs 1 kg (about 2.2 lbs). That’s 16*1000 = 16,000 ng of bisphenol A in 5 gallons of water (that’s 16 micrograms).
In mice 0.025 micrograms per kilogram per day was enough to cause “permanent changes in genital tract” (source: Wikipedia). Applied to a small human (50 kg) that would be 1.25 micrograms per day. The dose you would get from the polycarbonate at 1 gallon per day would be about 3.2 ug per day. So, even after I jacked up all of the figures we are still looking at just a little bit above the absolute lowest dose where something happens–IN MICE. The EPA has set a threshold of 50 ug per kg per day in humans so this is nowhere near that, of course.
My conclusion is that although it is possible that leaching of bisphenol A from plastic containers can cause some health problems, it is HIGHLY unlikely and you are most certainly being exposed to comparable levels of that chemical and others just by walking outside or going for a swim or drinking tap water (look at the levels of chloroform in tap water–though it’s not a big deal it’s about as big of a problem as bisphenol A). I think you are placing an inordinate amount of concern around this issue. I think that the benefits gained by using a container that suits your needs without worrying about bisphenol A are much greater than the risks imposed by the leaching.
Not to mention there is a finite amount of bisphenol A in a container and this, of course, will cause less and less to be leached each time you use it until it leaches infinitesimal amounts. If you’re very concerned, add some boiling water to it a few times to leach most of it out. It looks like in food containers the total amount of bisphenol A is 347 ug/g on average. So, for a 1 kg container that’s 347 mg or 0.347 g. That seems like a significant amount but the key here is the amount of time it is dosed out and the size of the dose. It’s very likely someone could take 0.347 g of bisphenol A all at once and live and have little damage because it would all be metabolized quite quickly.
Anyway, I think I’ve explained the hell out of this. If you made it all the way to the end I have much respect for you. Keep up the good work!
Sources:
Wikipedia
Yamamoto, Takashi, and Akio Yasuhara. “Quantities of Bisphenol a Leached from Plastic Waste Samples.” Chemosphere 38, no. 11 (May 1999): 2569–2576.
Hi Jake – I really appreciate your comments. Concerning both – I’ve found that emergency preparedness research is as saturated as the field of diet and exercise. One day we’re told not to eat salt, the next salt is okay. Then eggs are bad, then they’re okay. The research goes on and on without any statically conclusive results. Water storage is similar in regards to the fact that I have found mountains of research seeming to substantiate both the argument that leeching is a legitimate cause of concern and that it’s not. The same goes for the bleach efficiency. So considering that I have yet to be 100% convinced of the safety of leeching or the shelf life of bleach, I have chosen to post a cautious approach for the safety of my readers. I appreciate your comments however and welcome anyone and everyone to look into evidences against these two and make their own judgement as to its safety.
I kept several quarts of water, treated with chlorine bleach in military plastic canteens for about 3 years before I used them. I was at a remote location with my family and we were all thirsty and did not have any available water in the area.
This was why I had the canteens in the first place, so I broke them out. I drank first because of the time they had been in storage. I passed them on to the others and we all drank from the 3 year old water and found it to be palatable and healthy. No one complained about the taste and we had no problems from it.
Chlorine Bleach treated water in opaque containers is now my storage method of choice and I change it out slightly longer than once a year.
We have a food bank at our church; but years ago we got a large shipment of cleaning supplies and bleach. After a while the bleach will eat through it’s on container. I suggest you store it in a hard/thicker plastic bottle or a glass jar would be best.