The ability to treat and purify water is absolutely essential in any survival situation.
Clean water is a vital resource. Untreated water may contain invisible pathogens, including protozoa (parasites like cryptosporidium and giardia) as well as many different types of bacteria and viruses. You do NOT want to get these bugs anytime, let alone during an emergency. If you drink contaminated water and just get a horrible case of diarrhea, you actually got lucky! Some of these bugs take MONTHS to resolve with proper treatment.
When an emergency hits, stored clean water is only part of the solution.
Reliance on stored water really only works in shelter in place scenarios. Even then it will eventually run out unless replenished.
If we’re forced to leave our homes, or simply struggling to get back there, we must be able to create potable (drinkable) water while on the move.
Given water’s bulk and unwieldy weight of 8.34 lbs. per gallon, a person can only comfortably carry around three gallons. 25 lbs. of water slows anyone down. That weight is in addition to whatever survival items you’re hauling. Injuries could change the game entirely. And having your hands free to scramble over/clear obstacles, use equipment or defend yourself might be necessary. If water is in short supply, lugging huge jugs of water with both hands during an emergency could make you a target. Even if you have a half ton military truck with built-in, massive water storage, you’re still toast without a way to treat water. What if it breaks down? What if the roads become impassable?
Fortunately there are many effective options when it comes to portable water treatment.
Given water’s importance, I believe everyone should have several different methods to produce potable water. When something is incredibly essential, redundancy is king. Aside from boiling water, no single filtration or disinfection treatment method will eliminate all pathogens. Luckily, water treatment is one aspect of preparedness that is relatively inexpensive. We can all enjoy the peace of mind several treatment methods provide while leaving our bank accounts relatively unharmed.
Here, we’ll examine these options (starting with the most effective at eliminating pathogens down to least effective) so you can determine which work best for your situation.
BEST – Boiling
For thousands of years humans have boiled water to remove pathogens and make it safe to drink. Boiling water is the most effective water treatment method available. It effectively kills ALL types of pathogens ( protozoa, bacteria and viruses). Boiling eliminates microorganisms resistant to chemical treatment and those too small to catch through filtration. The CDC recommends bringing water (in a clean pot) to a rolling boil for at least one minute, three minutes at elevations greater than 6,562 feet.
- Pros – Extremely effective, inexpensive, doesn’t require specialized equipment and is best for silty water. Offers some protection against agricultural runoff such as pesticides and herbicides.
- Cons – Slow (must heat water then wait to cool), labor and fuel intensive, and will not remove chemicals/bad tastes/bad smells/color/sediment/turbidity (cloudiness) from water.
- Practice Pointer – Boiling is useful to treat water with very high sediment levels that would otherwise clog filters and resist UV light. A rolling boil causes sediment to settle, leaving clear water at the top.
SECOND BEST – Combining Filtration AND Disinfection / Purifiers
Coming in a close second place to boiling, combining a quality filtration system alongside a disinfection treatment eliminates most microorganisms in untreated water. Combination treatments, or using a water purifier, are extremely effective at killing all pathogen types, including protozoa, bacteria and viruses. Filtration catches the bigger microorganisms and disinfection bats cleanup taking care of the viruses. Keep reading for more information about filtration and disinfection.
Water purifiers use both filtration and disinfection, typically with a chemically treated filter or UV light treatment after filtration. Although purifiers are usually more expensive than standard pump and gravity filters, they eliminate the need to separately treat the water with chemicals. The EPA’s Guide Standard mandates that all water purifiers must, at a minimum, reduce protozoa by 99.9%, bacteria by 99.9999% and viruses by 99.99%.
- Pros – Effective elimination of all pathogen types, relatively fast (pump and gravity purifiers generally flow at 0.5-2 liters of water per minute) and multiple types of purifier systems are available.
- Cons – More expensive, require maintenance, can clog, heavier and more bulky than other methods, and may give water a bad taste.
- Practice Pointer – Using a activated carbon element can make water taste better while also reducing levels of some agricultural and industrial runoff. Very few other treatment methods reduce these.
BETTER – Filtration
Filtration uses microscopic pores to reduce pathogens by blocking bacteria and protozoa while allowing water to pass through. A variety of portable filters are available, including in-line, pump and gravity systems. Check back…in the near future we’ll post an article about the advantages and disadvantages of in-line, pump and gravity filter systems.
How many pathogens are eliminated depends upon the pore size of the filer, the contaminant level, the contaminant’s particle size and charge. Unless a filter is chemically treated (such as using iodine resin or activated carbon filters), filtration does not eliminate any viruses. Viruses are exceptionally small and pass right through filters.
Filtration is less useful near human waste, agricultural runoff and in undeveloped countries. For those in the US this isn’t much of an issue – viruses are rarely a problem in North America. But they are a massive concern in undeveloped countries. Even water from the tap in developing countries can contain viruses. Most filters will also not filter out chemicals found in agricultural runoff or heavy metals found near industrial sites and mining operations.
- Pros – Relatively fast (pump and gravity filters generally flow at 1-3 liters of water per minute), in-line filters are incredibly convenient and quick, and multiple types of filtration systems are available.
- Cons – More expensive, require maintenance, can clog, heavier and more bulky than other methods, and does not eliminate any virus types without chemical filters.
- Practice Pointer – If possible, collect water and allow it to settle before treatment. This will extend the life of your filter and reduce the need to backwash/unclog it.
GOOD – Ultraviolet (UV) Light
Ultraviolet light treatment methods irradiate water to kill or deactivate protozoa, bacteria and viruses. They do not remove them. They eliminate their ability to make you sick. All you do is activate the device, place it in the water and stir it for a short time (time varies by manufacturer).
UV light water treatment requires clear water to be effective. Turbid water requires pre-filtering. How many pathogens are eliminated depends upon water turbidity (cloudiness/sediment free water is required so light can penetrate) time, intensity, wavelength and type of pathogens present. It’s less effective against larger pathogens like protozoa since their larger size can act as armor to the UV light.
- Pros – Extremely fast, small and light. Effective against viruses (unlike filtration alone). More effective than tablet disinfection and, unlike tablet disinfection, does not leave a chemical aftertaste..
- Cons – Requires clean or pre-filtered water, requires batteries, is an electronic device (not useful in EMP/nuclear scenarios unless protected) and will not remove chemicals/bad tastes/bad smells/color/sediment/turbidity (cloudiness) from water.
- Practice Pointer – As UV light is only present in the water during treatment, any missed microorganisms can replicate and contaminate the water. It’s best to to consume water shortly after UV treatment, or re-treat/use a disinfectant if there will be any significant time before drinking.
OKAY – Disinfection (Chemical Treatment)
The least effective of all water treatment options, disinfection technology uses chemical treatments to reduce pathogens. There are 3 main types: iodine, chlorine and chlorine dioxide. All 3 are pretty equally effective versus bacteria and viruses. Disinfection is less effective at eliminating protozoa (giardia and cryptosporidium). Of the 3 types, chlorine dioxide tablets are the way to go. It is more effective against giardia and offers some protection against cryptosporidium (where iodine and chlorine offer little).
How many pathogens are eliminated depends upon time, chemical concentration, water temperature (more effective with warm water), turbidity, PH level and many other factors. As chemical manufacturers produce tablets in various concentrations, effectiveness varies.
- Pros – Very inexpensive, highly portable (take little space and weight almost nothing), easy to use and offer good protection against bacteria and viruses.
- Cons – Protozoa are very resistant to disinfection treatments, may leave chemical aftertaste, 15 minute – 4 hours wait times before water is ready to drink and only effective within several years of manufacture.
- Practice Pointer – Iodine and chlorine tablets have inherent risks. In addition to leaving an unpleasant aftertaste, iodine tablets are not recommended for pregnant women, people with hypersensitivity or thyroid problems, and shouldn’t be used regularly for more than a few weeks. Chlorine tablets may actually react with other substances present in the water, possibly forming toxic compounds. Chlorine dioxide tablets are the way to go.
DISINFECTING WATER WITH LIQUID BLEACH:
Liquid bleach is another useful option to disinfect water. In fact, the utility and versatility of bleach is so undeniable, we’ll be digging into all things bleach in a later post! However, we did not include liquid bleach in our above discussion for one reason – it has a limited shelf life of only around 4-6 months. But provided you’re willing to consistently rotate your supply, a sturdy eyedropper filled with bleach is a good option for water disinfection on the go.
To treat water with bleach:
- Filter or strain the untreated water to remove sediment. If not possible, allow sediment settle to bottom.
- Using regular (unscented) bleach, add 2 drops per quart / 8 drops per gallon.
- Double the above amounts if you weren’t able to filter the water or if it is cloudy.
- Wait 30-60 minutes.
- Smell the water. If it has a slight chlorine odor you’re good to go. It there is no chlorine odor, treat the water again using the same amounts and wait another 15 minutes.
So which one is best?
No method is the right or wrong. Each have their own advantages and disadvantages. It’s clear that some are better than others, but it’s up to you to choose what’s best based upon your personal situation. A purifier wins hands down over disinfection tablets, but you can’t throw a water purifier in your pocket. You can do that with tablets.
Water is essential for life. In a survival situation it remains essential and, unlike in “normal” life, becomes precious. We all must have several different, portable ways to create potable water.