Water Treatment during a Disaster Situation

Why Achieve Water Independence?

While in developed countries people tend to take safe drinking water for granted, 3.4 million people worldwide die of water related diseases.

Unfortunately, what most people who have access to clean drinking water today don’t realize is that the intricate system that provides them with safe tap or bottled water is very delicate, and under numerous scenarios is prone to complete failure.

For example – a blackout will affect both the water filtration and purification plants, as well as the pumps that move said water around. An EMP (such as from a solar flare or a HEMP) could knock such systems out permanently since most modern plants use SCADA industrial control systems. These are delicate electronic systems that are usually not shielded from EMP.

During the first gulf war, the U.S. military specifically targeted water and other infrastructure facilities, knocking out the vast majority of the systems by which Iraqi people maintained their society. Subsequently, in what I can only presume was a deliberate act of sadism, the U.S. government embargoed chlorine – a necessary chemical for the purification of water. The ensuing deaths of millions, including 500,000 children, was inevitable.

An industrial society with a high population density and a high degree of urbanization simply cannot survive without a complex network of water treatment infrastructure.

The question you should be asking yourself is this: If, for whatever reason, the infrastructure you currently rely on to obtain such vital necessities as water and food fail – what will your odds of survival be?

It is generally considered prudent to take out insurance against damages to your house, especially if you live in an area prone to natural disasters. And yet, it it democide – or death by government, that has been the leading cause of violent death in the 20th century. Governments are estimated to have killed in excess of 260 million people in the past century.

The first world war was initially called “The War to End All Wars”. Some people naively assumed that after the horrors of WWI, there could never be a repeat of such mass tragedy. Little did they know what the rest of the 20th century had in store for them.

It is almost infantile to assume that the wars and oppression that plagued previous generations will never repeat themselves.

If you are willing to take out health insurance in case something happens to you, and house insurance in case your property is damaged, then you should also be preparing for possible disruptions to the infrastructure that so many rely on to survive. So with that in mind – let’s review some of the ways in which you can become more independent of the centralized infrastructure in case something happens. I’ve split the rest of the article into two sections – filtration/purification and storage.

Making Water Safe

Ordinarily, unless you’re dealing with some kind of pristine mountain spring, water is contaminated by a wide variety of nasty things. In terms of effects, they range from diarrhea (which when dehydrated can kill), to deadly viral infections.

There are very many ways in which the safety of water can be improved. However, rarely will a single method assure you of safety. In no particular order, water can be: boiled, distilled, purified with ultraviolet rays, filtered through ceramics, filtered through handmade bio-sand filters, filtered through plastic membranes, and disinfected with chemicals such as iodine and chlorine. Some methods are well suited to dealing with some of the pathogens or toxins, while at the same time being completely ineffectual against other threats. I’ll try to go over as best I can all of the possible threats in water, and what methods deal with them best. At the end, I’ll go over what I’ve chosen personally to make water safe.

Possibly the purest water can be obtained through distillation, but this is an high-energy process which is very inefficient in the field, takes a lot of time to obtain a small amount of water, and difficult to do without some laboratory-type equipment. Water needs to be distilled at the exactly correct temperature, or some of the toxins will evaporate and pass through with the water vapor. Solar stills can be useful, but only during periods of intense sunlight, mostly during the summer.


Particulates can only be dealt with through filtration. A simple cloth filter will not work, however – removing only the largest pieces of debris. A good camping filter is best.

Disease Causing Protozoa and Cysts

Many protozoa, such as Cryptosporidium, will act as parasites and cause disease in humans. Luckily, protozoa and cysts such as Giardia are significantly larger than bacteria, and even low-end commercial camping filters will handle these with ease. They can be both physically removed, as well as destroyed by chemicals or through heat (boiling). Ultraviolet purification methods will also function. While these pathogens can be very dangerous, they’re also very easy to deal with.


Bacteria are responsible for such unpleasantness as cholera, botulism, and typhoid, among others. Luckily, bacteria are also vulnerable to chlorine disinfection, UV, and boiling (with the possible exception of those bacteria which live in hot springs). Any filter that is rated to a pore size of 0.2 microns or less will physically remove bacteria from the water.

However, be aware that the micron rating of a filter is often very ambiguous. The vast majority of companies only cite an average pore size. For example, all ceramic filters will have slightly differently sized holes – some of which will be too big and allow bacteria to go through. That is why they are, for example, rated to remove 99.99% of bacteria, and not 100%.

There does exist a type of filter (plastic membrane) which has a far more precise manufacturing process, and they can assure an absolute pore size. An absolute 0.1 micron filter, for example, would be guaranteed to have all of its pores be no bigger than 0.1 microns, thereby removing all bacteria, protozoa, and cysts. The filter I use is rated to remove 99.99999% of bacteria. I’d say that was pretty good.


Currently, viruses don’t tend to be a threat in the developed world. Unless you specifically suspect viral contamination of the water supply – you’re unlikely to run into them. The key word is currently. The developing world is replete with viruses in the water, and I presume this can be expected to occur within a fairly short period of time after a collapse of the current water processing infrastructure.

Viruses are usually not filtered by any filters on the market. There are a few exceptions, such as the lifesaver bottle and one of the Sawyer filters. In order to reliably filter viruses, you need a pore size no larger than 0.02 microns, as viruses are significantly smaller than the smallest of bacteria.

However, viruses are still plenty vulnerable to chlorine disinfection and boiling in water, so both of these methods can be used as a post-filtering safety measure – a sort of one-two punch. Ultraviolet purification will work too – essentially de-activating the genetic code of the virus.

Toxins, Dissolved Chemicals, Heavy Metals

This didn’t used to be a problem even as early as a century ago. But after WWI, the use of fertilizers, pesticides, herbicides, and other chemicals in agriculture exploded by orders of magnitude. That means you have to be significantly more selective in where you draw your water from. If there’s a likelihood of agricultural or industrial runoff , merely boiling won’t do. In fact, regular filtration won’t help much either.

This is where distillation is best – but as mentioned before, distillation can be difficult to do well. An activated charcoal filter, which can simply be added on after your regular filtration system, will tend to reduce the amount of dissolved toxins and heavy metals present in the water. Katadyn make a carbon cartridge for this exact purpose. It might be a good idea to run suspected water multiple times through the charcoal, or through multiple cartridges, because the charcoal will remove more of the chemicals with every pass.

So what do you use?

Step 1: The Filter

After reading about and using many different types of water treatment systems, I’ve decided to settle on four methods of water filtration and purification. Some are backups to be used if all else fails. (Disclaimer: I am not being paid to advertise any of these – I genuinely believe they’re a good idea.)

My filter of choice is currently the Sawyer squeeze 0.1 micron filter. They make one that takes out viruses too, but I think that the 0.02 filter will clog up faster. The primary advantages of the Sawyer filter is that:

1. It has no pump mechanism to fail.

2. It’s pore size rating is in absolute, and not average terms like most filters on the market.

3. It’s significantly cheaper than your average ceramic filter.

4. It weighs a mere 3 ounces, and

5. As long as the membrane isn’t damaged, it can be cleaned by back-washing and reused far more times than any other filter I’ve found. They have a somewhat ridiculous marketing guarantee of 1 million gallons – but given the difference in technology, it’s not that absurd. To clean a ceramic filter, you have to physically scrub off the top layer of muck. This also reduces the size of the filter, until eventually the filter is worn out and the cartridge needs to be replaced.

Beware: Filters Fear Cold!

You need to keep in mind that both membrane and ceramic filters are vulnerable to cold. If water in the filter is frozen and expands, the filter can be damaged. For this reason, if out in the field in sub-zero temperatures, I suggest you carry the filter in a coat pocket close to your body so that it doesn’t freeze. At night, bring it with you into your sleeping bag (get rid of most of the water first).

Step 2: UV Purification

I use a handheld UV purifier made by Steripen. The idea is simple – you immerse it in the water needed to be purified, switch it on, move it around for a minute or two depending on the quantity of water, and all the pathogens are destroyed. It’s an excellent backup to make sure that pathogens are taken care of in case the filter is damaged or if you suspect viral contamination.

Some form of pre-filtration is absolutely necessary, as particulates in the water will significantly reduce the ability of the UV to penetrate the water and kill pathogens. I have a quick Youtube video in which I describe the system I use, which includes a small solar panel for recharging the batteries and still weighs under 8 ounces.

The obvious disadvantage is that a piece of electronics may fail for numerous reasons, and of course the bulb itself will eventually fail, being good for approximately 4000 litres.

On the other hand, while the system works, it allows me to purify the water without using harmful (iodine) or badly tasting (chlorine) chemicals, and without making a fire and waiting for the water to boil every time. I find that when water is chlorinated, I drink less than I should because it is disgusting to me, and as a result I end up dehydrated. Besides which – to carry 4000 litres worth of chlorine with you would be a lot more difficult.

Step 3: Boiling

I have a titanium bottle-slash-pot that can be placed over a fire and used to boil water. If you use a plastic bottle such as a Nalgene, you’re going to need to carry a separate metallic cup or pot to boil in. Aluminium is a bad idea – use either steel or titanium. This is a backup in case step 1 and 2 fails.

Step 4: Backup chlorine tablets

This is the last-ditch backup, in case for whatever reason I can’t get a fire going (too wet – need to maintain a low profile when escape & evading, etc.) Just place the tablet in your water container and wait.

The filter weighs a mere 3 ounces, the rechargeable UV system less than 8 ounces, the bottle doesn’t count because it’s my water carrier, and the backup chlorine tablets weigh significantly less than an ounce. As a result, for less than 12 ounces of additional weight, I have four methods of making water potable. This certainly satisfies the survival rule of threes (three ways to obtain safe water, three ways to obtain food, etc.), while still weighing less than most conventional pump filter systems alone.

Prepare yourself now – while it’s cheap and easy

The filter I use together with a stainless steel bottle can be obtained for less than $100. Chlorine tablets are very cheap. The UV purifier costs another $100 and is more of a time-saver than anything else, as boiling will have the same effect.

I intend to add another step – activated charcoal. A simple carbon cartridge and a bunch of charcoal will cost less than $50, and will significantly improve the taste of water, while also reducing many of the chemicals and heavy metals that other methods won’t remove.

At very low cost, you currently have the ability to purchase (and practice using!) multiple technologies for water filtration and purification. The membrane, UV, and chlorine technologies I talk about are all used in large water treatment plants around the world. You can obtain smaller versions of them quite cheaply. During or after a disaster, such an opportunity will vanish, and you will be forced to buy questionable bottled water at a high cost – if such will be available at all.

I suggest you think about your water insurance now, while it’s still cheap and easily accessible.

Potable Water will be a Prized Barter Good

Consider that during a disaster situation, while others will be scrambling for the few bottles of water available, you will have a method of obtaining safe water in fairly large quantities. Should you wish, you could trade that water for other survival necessities, such as more food. I’m sure your thirsty customers will have plenty of empty bottles for you to fill.

Storage and Water Sources

This section coming soon! Need to do more research first…

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