SurvivalBlog.com

James,
Your advice is excellent; however, one of the best tools to have for checking [water] sanitation levels is a DPD [Diethyl-paraphenylene diamine reagent] test kit available from Taylor or Hach, to name a few.
I do not recommend OTO [orthotolidine reagent] kits as they are not as accurate as DPD. A 5mg/L initial shock should take care of most contaminants.
After you have treated any water with bleach, it should be tested for free chlorine residual after 30 minutes of contact time. Water with a free chlorine residual of 4 mg/L should not be ingested for long durations as it can cause mild digestive tract issues.
NOTE: The suggested residual is between 0.5 and 1.0 mg/L (parts per million or ppm). The EPA requires all discharge to have less than a 1.0mg/L free chlorine residual before
leaving the process flow.
The great thing about chlorine is that it will kill 95+% of all the biological contaminants; however, chlorine cannot kill giardia cysts as their outer covering is very difficult to break down. One other potential problem with the use of chlorine to treat surface water is the formation of bromide compounds which are cancerous; however, unless the precursors, carbon compounds, are present the formation rate is very low. If you are treating a contaminated well, the chance of bromide formation is even lower.
If you can pre-filter and add bleach to your water then allow the free chlorine level to drop to 0.5mg/L, placing the treated water in an opaque, sanitized vessel for long periods of time should be fairly safe as long as the initial feed stock was fairly free of organic matter to begin with. Thank you for all your hard work keeping us prepared for what ever may come. Sincerely, – Drew

Jim:
Using calcium hypochlorite to disinfect water is a good idea. However, rather than trying to dump some amount of pool shock chlorine into a tank and hoping that it dissolves and mixes with the water, a better idea is to mix a slurry of it in a plastic bucket (it will corrode a metal one) and pour and mix the slurry.
Also, the halide (halogen, chlorine or iodine ions) need to be in contact with the water for some amount of time before they can kill all the bacteria – and that time is dependent on the temperature of the water. Colder water takes longer.
To test the degree of halogenation in water, I suggest that people get a pool water test kit and use it. They are very inexpensive, and easy to use: Simply get a (clean) bucket of water that’s been treated, and use the pool water test kit (for halogenation), ideal ‘pool water’ is about 2 parts per million (ppm) chlorine, drinking water should be between 2 and 5 ppm when treated – the chlorine will gas off over time, as long as the water isn’t likely to be re-contaminated (in an open top tank, for example) it doesn’t really need to be retreated. Dump the ‘test’ water out, [orthotolidine] OTO isn’t too good to drink.
The test kit will have directions but basically you put the test water into a clear chamber, add a reagent–usually orthotolidine (OTO)–to the chamber, and compare the color to the provided chart. If the water tests too low, add more slurry, if too high, next time don’t add so much. People will be able to figure out the approximate ‘right’ amount pretty quickly.
The military chlorination kits (for Lister bags and water buffalos) suggest as much as 10 ppm. This is to allow for high levels of organic material in the water (which adsorbs the chlorine, keeping it from disinfecting the water, and allowing the water to not be retreated too quickly); you probably recall drinking beverages so treated with as much fondness as I do. – Flighter [His article follows]

How to Disinfect Water, by Flighter

How to sterilize water? Simple: You don’t need to ‘sterilize’ water. Sterilization is the destruction of all microorganisms in, on and around an object. What is needed, is disinfection (killing of pathogenic (disease causing) organisms).
Disinfection can be done many ways, including filtration, heat, ozonation, and chemical disinfection.
Despite many stories to the contrary, simply boiling water will disinfect it. At any elevation you’re likely be at the boiling point of water is high enough to kill (or denature) anything in the water. You don’t need to boil it for any particular length of time, just get it boiling at a good rolling boil.
Filtration is a good method, you should use a filter that has an absolute rating of 0.2 micron diameter or less (0.1 micron). Personally, I use iodine crystals (Polar Pure™ first, then filter the water.
Chemical disinfection is the use of various chemicals (usually a halide like chlorine or iodine) in the water. It’s usually a quick, economical and effective method.
Here is a summary of water disinfection chemical usage based on the Wilderness Medical Society Practice Guidelines 2nd Edition, edited by William Forgey, MD (page 63):
For chemical disinfection, the key is the concentration of halogen, in parts per million (halogen to water):

Concentration of Halogen

How to get the desired concentration of halogens, for various products:
Iodine tablets, also known as: tetraglycine hydroperiodide; EDWGT (Emergency drinking water germicidal tablets); USGI water purification tablets; Potable Aqua (trade name); Globaline (trade name):
4 ppm – 1/2 tablet per liter of water 8 ppm – 1 tablet per liter of water.

NOTE: These tablets should be gunmetal gray in color when used – if rust colored, they are useless:
The free iodine has combined with atmospheric moisture. The bottles should be kept well sealed and replaced often. Checking the tablets in the bottle just exposes them to moisture in the air.For 2% iodine (tincture of Iodine) (gtts=drops)
4 ppm – 0.2 ml (5 gtts) 8 ppm – 0.4 ml (10 gtts)
NOTE: Tincture of Iodine should not be used as a wound treatment, so this is not a good option for a ‘dual use’ item.

10% povidone-iodine solution (Betadine™)
NOTE: Solution only, not the “Scrub”variety – Since Scrub has soap in it
4 ppm – 0.35 ml (8 gtts) 8 ppm – 0.7ml (16 gtts)

Saturated (in water) Iodine crystals (Polar Pure ™)
4 ppm – 13 ml 8 ppm – 26 ml

Iodine crystals in alcohol
0.1 ml / 5 ppm 0.2 ml / 10 ppm

Halazone tablets (Monodichloroaminobenzoic acid)
4 ppm – 2 tabs 8 ppm – 4 tabs
NOTE: The old Vietnam era chlorine tabs are decades out of date. Chlorine tabs decay even more rapidly than iodine tabs. Not recommended.

Household bleach (Clorox™)
4 ppm – 0.1 ml (2 gtts) 8 ppm – 0.2 ml (4 gtts)
Note: Bleach offers a relatively economical method of treating large (gallons) of water at a time. 4 liters is approximately 1 gallon.
For very cold water contact time should be increased.

If drinking this water after disinfection, flavoring agents (drink mixes, etc) can be added: This must be done after the period allocated for disinfection ([otherwise] the disinfecting agent will bind to the organic material and not work).

Jim:
I had to write you and correct something that could lead to health damage or even death from the use of chlorine [for water treatment]. People have to know that this use [of chlorine] is for treating water [shortly before use], not long term storage. If you have a water supply that you intend to drink/use within a month, then chlorine (as long as it’s pure – as you so instructed) is fine. But it is not for long term storage!
When water is treated with chlorine, and then sealed in a container, the chlorine degrades over a short time period. Depending on variables (mixture, amount of water, heat, et cetera) this could be as soon as 2-3 months. As it breaks down, it releases chlorine gas, which does nothing to protect your water, but it can cause health problems (obviously) and it will also degrade and weaken your container.
There are products out there that can be used for long term water storage. (Stabilized Oxygen is but one of them.) These products can keep water stored safely for up to five years, with no bacteria or algae growth. – Kurt

James Wesley:
I can’t remember where I got this, but thought it might help with the question of “how much” in chlorinating water…..

Chlorination
Two common forms of chlorine compounds can be used, those disinfectants that contain Sodium Hypochlorate (household bleach) or Calcium Hypochlorate (swimming pool chlorine powder). It is very important that Chlorine is added to water at the correct dosage. Firstly, calculate the amount of water in the tank by using the following formula:
3.14 x radius2 x height of water in the tank (meters) x 1000 (The radius is half of the width of the tank)
Once you have calculated the volume of the water in the tank then place 40 milliliters of Sodium hypochlorite or 7 grams of Calcium Hypochlorite for each 1000 liters of water in the tank.
For example, if the tank’s dimensions are 5 meters wide, 3 meters high and there is 2.5 ml of water in the tank, the calculations would be as follows:
Volume of Water in the tank is:
3.14 x (5 x?)? x 2.5 x 1000 (liters)
Volume = 49,062.5 (liters)
40 x ( 49000/1000) = 1960 mils of Sodium Hypochlorite
Or 7x ( 49000/1000) = 343 grams of Calcium Hypochlorite

Regards, Terry M.

Mr. Rawles,
I want to buy some pool chlorine crystals for long term storage. Holly Deyo’s book had a formula for purifying large amounts of water with this product, but how would I make a chlorine bleach substitute that could be used to purify smaller quantities of water or as laundry bleach? Is there an amount in grains or grams that could be used to make up, say, five gallons at a time? I know store bought laundry bleach like Clorox has a limited shelf life, so I wanted to be able to make [my own hypochlorite solution.] Thank you for any information you could provide. – CG in North Carolina

JWR Replies: Calcium hypochlorite is available from any swimming pool supply company. A granular (dry powder) “pool shock” product that lists only Calcium Hypochlorite as the active ingredient should be safe to use for water purification. The problem with other varieties is that they include other algaecide or fungicide chemicals that are probably not safe for human consumption. Ditto for using liquid bleach for the same purpose. With those, you want to buy plain Calcium Hypochlorite bleach. Do not buy bleach with fabric softeners, scents, et cetera. Keep in mind that bleach solutions break down and weaken with time (anticipate a 24 month shelf life), but that dry granular bleach stores indefinitely. Here is a quote from an EPA web site: “Granular Calcium Hypochlorite. Add and dissolve one heaping teaspoon of high-test granular calcium hypochlorite (approximately 1/4 ounce) for each two gallons of water [to create a chlorine disinfecting solution]. The mixture will produce a stock chlorine solution of approximately 500 mg/L, since the calcium hypochlorite has an 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 oz.) of stock chlorine [solution] to each 12.5 gallons of water to be disinfected. To remove any objectionable chlorine odor, aerate the water…”

SurvivalBlog reader Laurelei recently reported that she found the Poolife brand “TurboShock” available $14.85 for five pounds. For purifying drinking water, two of the five pound boxes would constitute a “lifetime supply” for most folks.