Decontamination and Sterilization of Water

We usually take water for granted. While water is almost never scarce in most areas, uncontaminated water might become very scarce following a wide-spread disaster like a nuclear war or economic collapse during which all pollution control endeavors were abandoned.

Next to the air, we breathe, water is probably the most important thing for your long-term survival. Though it’s possible to go without food for a month or more, without water, you’d be lucky to survive for more than a few days.

Fortunately, no matter how contaminated water may be by dangerous organisms, nuclear fallout, or chemicals, it is seldom so contaminated it can’t be decontaminated and used. Water can’t be damaged. If you can remove the contamination or neutralize it, you will have water you can use for drinking, washing, or cooking.

Of course, you must have a source of water. So your first step toward survival is to locate the springs, wells, streams, etc., in your area so that you will have a good source of water. Find a reliable source of water.

Tainted Water

How much water will you need?

Unless you have a well or spring in your house or yard or have a cistern (a large storage tank designed to collect rainwater), you’ll probably have to carry water to your house. That means you’ll have to do with a lot less water than you now use.

The amount of drinking water you’ll need is fairly easy to figure. A human being should have at least a gallon of water per day during hot weather or two quarts per day if the weather is cool, the person doesn’t need to do heavy work, and no water is needed for cooking or cleaning. (There are a lot of “ifs” with the two-quart-per-day amount, so it’s safer to plan on a gallon.)

Chances are, even if you have a large source of water nearby, you’ll want to store some water. This will allow you to worry about things other than your water supply during the first few weeks of a major disaster.

During a disaster when there might be looters about willing to take pot shots at you, the prospects of dragging gallons of water back to your home or shelter isn’t too great of a survival strategy. Nor is dancing through the fallout to get drinking water. It makes a lot of sense to store water for just such emergencies.

How to store your water

There are a lot of ways to store water. Your first task is to find a place to store it. It should be kept where you can get to it from a fallout shelter without exposing yourself to fallout (and remember that water is fairly good as shielding for your shelter).

Remember, too, that water is heavy. Don’t store it where its weight may cause structural damage to your home. If you’re where nuclear bomb shock/ blast waves from a close target aren’t a concern and aren’t in a major earthquake area, then a swimming pool or large tank could be used to give you a huge supply of water.

Most of us aren’t in such an area, however, and need to use tough storage containers capable of surviving a little punishment. Storage containers can cost a lot of money.


Fortunately, if you’re like most Americans, a lot of potential water storage containers are available to you in the form of soft drink and milk containers. A second good source is available in the form of used food containers available from grocery stores, restaurants, etc., for free or a small price.

With a little cleanup, these are ideal for storing water. All you need to do is to be sure the container was designed for food. Don’t use plastic, which is not designed for food storage since it may contain chemicals that will leach into the water, which is stored in them.

My favorite containers are two-liter pop bottles. These are tough and easy to move and handle. Plastic milk containers work, too, but seem prune to leakage if they are abused in the least bit.

Read next: Emergency Water Storage Solutions

Don’t use glass containers as these can be quite dangerous or may break under the rough-and-ready conditions of a disaster. Things are bad enough during an emergency without having broken glass scattered over your living area, and your water supply suddenly down the tubes as it were.

Containers larger than two gallons are harder to handle. Probably the upper limit for practicality is the five-gallon plastic storage containers that are available from a number of survival stores. When working with any container that’s this large, it’s a good idea to place it where you want it and then fill it; otherwise, you risk wrenched muscles, a bad back, or even a hernia!

Also, remember that any filled container, even a two-liter pop bottle, is dangerous if it falls from any height. Secure water storage bottles so someone doesn’t get seriously injured by them.

Contaminated Containers

In addition to avoiding plastic containers that are not designed for storing food or water, find out what was in used containers before storing drinking water in them. If they contained any petroleum products or—worse yet—poisonous chemicals, do not use them for storing drinking water.

The chemicals will often get into the containers so that there is no way to clean them out. Metal containers should be chosen with care so that they don’t rust out; the water can also take on some odd tastes when stored in metal containers.

In general, plastic is much better than metal or glass containers for water storage. In his Nuclear War Survival Skills, Cresson H. Kearny shows a good “expedient” water bag that is made with two large plastic garbage bags nestled inside a pillowcase or gunny sack. This arrangement allows the cloth to support the plastic bags while the double wall of the plastic bags holds the water.

These bags work well, provided you have a good way to support them, and are careful to secure the opening.

Kearny also offers another excellent way of using plastic sheets to create a pool of water. First, take some shower curtains, raincoats, or whatever, and line a hole dug in the ground with them. Fill the hole with water, then cover it with another sheet of plastic and a board to prevent evaporation. There you have it, one pool of water to be used later on.

Except for the last water storage system, care must be taken with any water in a sealed container to be sure it isn’t allowed to freeze. Ice can rupture most water containers, and your supply of water will then be lost when warm weather comes along again.

Damaged Water Facility

Large containers are hard to get water out of. One way of easily doing this is to use flexible plastic tubing to drain or pump water from them. This is better than dipping water out since you’re less apt to spill water and won’t get the foreign matter into the water.

A hand pump isn’t essential to remove water from large containers if you have a length of hose that can be used to siphon the water out. The secret with siphoning is to have the top of your source of water higher than the point at which the water is to end up.

The hose itself must be submerged in the water source, but the water can travel above or below the level of either the source or the outlet on its “trip” through the tube. The flow of water is started by sucking on the end of the hose (soda straw-wise). The vacuum created by the falling water will pull more water out of the water container, and it then drops to the level of the outlet.

To stop the flow, bend or pinch the tube shut or raise the outlet end above the level of the source of water. Also good is a hose clamp, which is available at most plumbing supply stores.

To save water ordinarily used for personal hygiene, pre-moistened towelettes can prove very useful. These towelettes are good at cutting through grime and grease. I feel the best are those designed to be used in cleaning babies. These towelettes are available in most grocery stores around the baby food section. One box of these will save you a lot of water.

If you have to haul water from any distance, you’ll also want to do a minimum of dishwashing. Forget manners during a crisis: eat out of food containers and have family members “lick clean” their utensils. Have each person use the same utensils for the next meal, and there will be little danger of spreading diseases. Also, have a supply of plastic “picnic” utensils, paper plates, styrofoam cups, and paper napkins to use with messy foods.

How safe is the water stored for months or years or gathered from a nearby stream to drink?

The answer is simple: it may not be at all safe to drink.

Sterilization of water

It’s not hard to see why water that is taken from a stream or pond might be contaminated. But why would water taken from the tap and stored in sealed containers be dangerous?

Most modern municipal water supplies depend on chemical treatment to keep the numbers of bacteria in them at safe limits. The water isn’t sterile; it is usually full of bacteria. But their numbers have been lowered to the point that a healthy child or adult can overcome the organisms.

However, if the water is sealed up for even a few days, the chemical (usually chlorine) will “wear out” as it continues to kill the bacteria multiplying in the water. When the chemical has dealt with a number of bacteria, it “wears out” and the germs will be able to multiply unchecked to potentially dangerous levels.

While these may not be capable of killing you, they might give you one heck of a stomach upset. And you’ll have enough to worry about in a disaster without hitting the bathroom every 10 minutes.

So, for survival purposes, you should treat or sterilize any water after it has been stored for any time at all or if it comes from a source where dangerous organisms may be present.

The simplest way of making water safe to drink is to boil it—at a full boil—for at least 15 minutes. Notice that you don’t just boil the water. You have to boil it for 15 minutes after it starts to boil; simmering time does not count. Water that’s not boiled long enough would be dangerous to drink.

Boiling water is not too practical in some emergency situations. In such cases, using chemicals to kill the bacteria in the water is a lot easier. There are a lot of ways to do this. In addition to water purification tablets, two useful chemicals for sterilizing water are 2 percent tincture of iodine, and sodium hypochlorite—the active ingredient found in most household bleach.

With 2 percent tincture of iodine, use five drops per quart of water; with 5.25 percent sodium hypochlorite solution—bleach—use two or three drops.

Double the amounts if the water is cloudy or smells bad. As with boiling, the killing of the organisms in the water is not instantaneous; let the water stand for a half-hour before drinking it. Tincture of iodine is the most effective of the two in killing bacteria and has a lot of other uses as well, but it also tastes worse than hypochlorite solution (since most of us are used to tasting chlorine in our water).

Iodine crystals can also be used but aren’t too practical and can be quite dangerous if mixed up in the wrong proportions, which is easy to do. My advice is not to use iodine crystals for water sterilization.

Either hypochlorite or iodine should be replaced every few years since they’ll lose their potency over time. If you fail to do this, you’ll need to increase the dosage slightly to make up for the loss of potency.

Important: remember that both these chemicals are poisonous; keep them out of the reach of children, and for the same reason, don’t use too much of any of the chemicals.

Water purification tablets are very handy to have. There are two types: tetraglycine hydroperiodide (an iodine compound) and halazone tablets (a chlorine compound). The tetraglycine hyproperiodide is much better to use than the halazone tablets. Some viruses and amoebic cysts are not killed by the halazone. The iodine compound is sold under a number of trade names: Potable Aqua, Aquatabs, and Coghlan’s, among others.

Water Purification Tablets

Like the tincture of iodine, tetraglycine hydroperiodide tablets slowly lose their potency. If they are kept sealed, are not exposed to bright light, and remain in a cool area, they are good for four years or even more. Halazone tablets last an even shorter time; they’ll remain useful for only two years if kept cool and sealed airtight.

Because of the short shelf life of these tablets, avoid military surplus purification tablets since they’ll probably have lost their ability to kill organisms that might be in the water by the time the government has unloaded them.

Follow the directions on the purification tablets’ container. For most tablets, this means one halazone tablet per quart of clear water; with chlorine tablets, five per quart; and Potable Aqua tablets, one per quart. Double the number of tablets for hazy or foul-smelling water. Again, it takes time for the chemicals to work, so be sure to wait for 30 minutes after the tablet has dis-solved before using the water.

Chemical contamination can be removed from drinking water with an activated carbon filter. These are easy to make and use. If you have the money to invest in survival gear, I recommend the Big Berkey Gravity-Fed Water Filter. I can honestly say, it’s worth its weight in gold!

Fallout and sterilization of water

During a nuclear war, water from a pond, stream, or river might also contain fallout. While the radiation from this fallout might be at a safe level for outside your body, the inside of your body is much more sensitive to radiation damage and will store some isotopes in certain organs of the body where they become dangerous because of their higher concentration. Therefore, you need to go through an extra step before you sterilize any water which might have fallout in it.

Fortunately, most fallout particles are heavy enough that they will fall to the bottom of a body of water and will soon be covered with sediment. Fallout doesn’t harm water, and any radioactive particles in water can be filtered out of it. While there may still be radioactive trace elements in the water in a gaseous form, these will be quite small, and at safe levels, by the time you can be outside a shelter looking for water.

Water Drops

One method of filtering fallout out of water is to strain the water through a paper towel or several layers of clean cloth (we’re assuming that neither cloth nor towel is contaminated). Another good filtering material is a coffee filter designed for an automatic coffee maker. With any of these, the water should flow slowly through the material into a second container.

Don’t try to overuse your filter; discard it after you’ve used it for a while. And remember that the filter will become full of potentially dangerous radioactive particles.

A more efficient filter can be created with a five-gallon can or bucket. Punch small holes all over the bucket’s bottom, cover the bottom with several inches of cleaned small rocks (or—in a pinch—twigs), spread a finely woven cloth over the rocks, and on top of the cloth place 7 to 10 inches of soil (sandy soil won’t work but any other type of dirt will).

Recommended article: Decontamination Procedures for Biological and Chemical Agents

To filter water, let the water trickle into the top of the earth filter and place a container under it to catch the water as it drips out of the bottom of the can or bucket. This water must be sterilized before you drink it. Again, after the filter has been used for a while, replace the rocks, dirt, and cloth and start over. Again, remember that high levels of fallout may be present in the filter material.

Even if you can’t filter water that may contain fallout, you can do a lot to minimize the amount of fallout you ingest. First, don’t get water near the bottom of your source of water since fallout will tend to be in that area. After you’ve collected the water, allow the water to sit, undisturbed, for 24 hours in its container so that fallout particles will settle to the bottom.

When you use the water, disturb it as little as possible and carefully and slowly pour the water from the container. Leave the last of the liquid (with any fallout) in the container, and be sure to dispose of this water and fallout particles carefully.

Again, be sure to sterilize the water after filtering it since dangerous organisms may be in it.

Stored water and the chemicals used to treat water both can taste pretty awful. Therefore, you’d be wise to use the “trick” used by many GIs and troops around the world: put instant tea, Kool-Aid, etc., into your water to “camouflage its bad taste.


Normally, water won’t be hard to come by following a nuclear war or another major disaster, and it’s nearly impossible for water to be contaminated to such a point that it can’t be used. Provided you have a little know-how in making it safe, you’ll have drinking water to use in an emergency. Sterilization of water requires following some basic rules and avoid rushing into it.

You may also want to check this:

Knowledge to survive any medical crisis situation during a major disaster

Learn how to Safeguard your Home against Looters

Find Out What’s the Closest Nuclear Bunker to Your Home

The vital self-sufficiency lessons our great grand-fathers left us

3 thoughts on “Decontamination and Sterilization of Water”

  1. I have worked in many disaster areas around the world as a helicopter and airplane pilot. I discovered the Steri-Pen nearly 20 years ago and have used it extensively. I treat all my foreign water with one and have never gotten sick from it. My daily water is carried in Lexan bottles. I use Lithium batteries for long life and have never had a Steri-Pen fail me.


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