Long Term Water Treatment Methods

long term water treatmentMike wants to know more about long term water treatment methods.  Mike will be participating in my upcoming Intro to Backpacking event at Hariman State Park with Hudson Valley Hikers. Mike asks:

What’s the best long-term method of water filtration? E.g. Trump leads us into nuclear war, city water will be undrinkable for 5 years and you can no longer buy whatever filtration straw, tablet, etc, and we all retreat to the woods for survival…

Long Term Water Treatment Methods

All right, let’s say a very desperate Hillary Clinton leads a coup against President Trump. A civil war breaks out, Trump goes nuclear, and we’re all living in the Hunger Games. How do we get drinking water?

Sawyer Squeeze and other Filters

These days, most AT thru-hikers are preparing their daily water using the Sawyer Squeeze filter. The full size Sawyer Squeeze (not the mini) will clean up to 1 Million gallons of water so long as you keep back flushing it to restore flow. The back flush procedure is very simply and only takes a few minutes. Either the original or mini sawyer squeeze filter will remove 99.99999% of bacteria and protozoa. This filter will work very well for surviving in the woods of North America during the non-freezing months of the year.

Hikers filter water and refill their bottles along the Appalachian Trail.
Hikers filter water and refill their bottles along the Appalachian Trail.

Like all micro-filters, the Sawyer has some drawbacks.  First of all, it doesn’t remove viruses toxic chemicals from the water. Most of the time in our neck of the woods, this isn’t a problem. If you’re high up in the mountains and above any farms or factories, the chances of encountering viruses or chemicals are very low. The virus problem can be countered by additionally treating your water with UV light or a chemical treatment like Aqua Mira or by boiling it. To remove chemicals, you need a better pump or a still.

First Need and other Water Purifiers

If things have gone down hill fast or if you’re traveling overseas, you need to be a little more concerned.  In particular, third world countries notoriously have very poor standards for pollution control and you run a higher risk of running into viruses or chemicals.  If this is the case, you need a better filter, like the MSR Guardian or General Ecology First Need.  These filters are heavier and are more work to use, but  they remove viruses, chemicals, and tiny bacteria that are missed by most simpler filters.

The first need water filter will remove viruses and some chemicals.
First Need Water Filter

The long-term draw back of these more advanced filters is that they need replacement cartridges.  When you run out of replacements, the filter becomes useless.

All filters have another common weakness: You must keep them from freezing. If the residual water in a filter freezes, expanding ice crystals will increase the diameter of the micro tubes and will allow larger contaminants though. While smaller filters can be kept close to your body to prevent freezing, this practice may not be practical with the larger pump filters.

Boiling and Distilling

The best long-term water treatment method for all locations and all times of year is boiling and distilling. Boiling will kill nearly all biological contaminants.  Boiling water for 5 minutes should make it completely safe in most situations.  Distilling will remove most chemical contaminants and salt.  Boiling water only requires a good container and good fire starting skills. (I can never emphasize enough that all backpackers and hikers should practice building a fire in adverse conditions.)

Distilling water is also pretty easy. Carefully drape a plastic sheet or bag over your boiling pot so that it catches the steam. The drops of water that condense on the underside of the sheet are clean and safe to drink. In the event that you don’t have a fire, you can use sunlight to evaporate the water and the condensation will still be clean.

boiling is the best long term water treatment method
A scout boiling water over a Wood gasifier Stove