Portable Water Filters
by Byron KirkwoodOriginal publication date February/March 1997I am often asked, "Which water filter should I buy." I am usually tempted to answer with, "The best you can afford." But then, I take a few minutes and question the person's need for the water filter, and try to determine the best recommendation for their particular application and financial resources.
When we are thinking about portable water filters, in contrast to a water filter that is permanently attached to your water supply, I divide the choices into two main categories: those useful for emergencies and those for survival.
I consider an emergency a short term situation where things will return to normal in a few days, typically within 72-hours to a couple of weeks. A survival situation I consider a lot longer, maybe anywhere from a month to tens of years. Why is this distinction important? Later I'll discuss replacement filters and how many gallons of water a particular filter will handle below.
For now consider the importance of water:
Gordon-Michael Scallion, of the Matrix Institute, once said that in the future there will be a time when water may be worth more than gold. In case this is hard to believe, just think about this simple example. Just imagine yourself in a hot desert and you're very thirsty, not having had anything to drink in a couple of days. You stumble upon an encampment where there's a person and he has several containers of water. You just happen to have a few gold coins in your pocket and the other person is willing to trade a gold coin (that's presently worth about $400 each) for a gallon of water (that would normally cost you a few pennies from the faucet). What would you do? At this point most people would realize that the water at that moment has more value than the heavy metal coins.
Think about the critical needs of our body to stay alive. First, we need air (oxygen). A person can go without air for only a few minutes. Next we need water. Depending on the environment, we can typically go without water for up to about three days before we die of dehydration. People can go without food for up to about three weeks. The point being, water is more important to our ability to stay alive than food. This is not to downplay the need for a supply of emergency food, only to emphasize the importance of drinkable/potable water. And most supplies of long shelf-life food are dehydrated or freeze-dried and need water to reconstitute and become edible.
I used the term "potable" water, meaning fit for human consumption, or that it is safe to drink. The old saying "Water, water, everywhere...but not a drop to drink" comes to mind when I think of the need for a water filter.
Rainwater, snow, surface water in streams and lakes ... all have the risk of being contaminated with germs, virus, and bacteria, that is harmful to us if taken internally, or in extreme cases, even dangerous if exposed to the exterior of our bodies.
Recent flooding has emphasized the need to be able to individually purify water. During some of this flooding the local water treatment plants have been overrun, causing the utility water to become contaminated. There are several ways to purify water, including boiling and the use of chemicals, but having a good water filter available is probably the best and easiest way to obtain potable water.
B&A carries two premier lines of water filters: Katadyn and SweetWater. Katadyn, made in Switzerland, has been the standard in water filters for many years. Their filters are used by the International Red Cross, the Peace Corps, the United Nations, the World Heath Organization, missionaries everywhere, and many others. SweetWater is fairly new, but have introduced less expensive units designed for campers and outdoor enthusiasts. Both companies have excellent products. Typically, I recommend the Katadyn ceramic-based products for survival, and the SweetWater products for handling emergencies, and camping and outdoor applications.
The Katadyn Pocket Filter (PF) has been considered the best available for many years. It uses a ceramic filter with a 0.2 micron pore size that will not allow harmful bacteria to pass. The ceramic filter is impregnated with minute quantities of silver to kill off microorganisms. Like most water filters, the PF is designed as a pump unit and the water is filtered by hand-pumping action where a hose drops into the dirty, unfiltered water, and the clean filter water exits out a spout into a separate container. The PF was originally rated to be able to handle 5,000 gallons of filtered water before the ceramic filter needed replacing, but further testing has extended its useful life to 13,000 gallons. The PF filter is the most expensive to purchase, but the least expensive if the price is considered on a per-gallon basis. This is the unit I recommend for survival applications if you are on the move. It is also the unit I provide in my top-of-the-line emergency kit.
Katadyn's next unit is their Mini Filter (MF) that also uses the same type of ceramic filter, only smaller, and it is rated for 2,000 gallons before the filter needs to be replaced. The MF is ideal for those traveling to other countries than need to protect themselves from the local water (i.e.: Montezuma's Revenge). It is also the unit I provide in most of my custom emergency kits.
The Katadyn Drip Filter (TRK) uses the same ceramic technology but is a larger unit. I tend to describe it as two thermos jugs, one on top of the other, where you pour the dirty water in the top one and the filtered water drips into the bottom one, that has a spigot on it. It is still portable, in that you can take it with you, but too large to fit into an emergency kit. The TRK is not a pump unit, but operates off gravity flow to filter the water. Thus, it doesn't require anyone having to pump it and can be left alone to filter the water. The rate of water flow is less than the pump units. The TRK top container will hold 2-1/2 gallons and it will filter 6 gallons of water per day. To me the ideal application for the TRK is where you have a cabin, or similar location, and need to be able to pour the water in, leave it alone, and later come back and have clean water available.
Katadyn has recently introduced another unit that uses two filter technologies to purify water. The COMBI filter has both a ceramic filter and an activated carbon filter. The activated carbon filter removes dangerous chemicals, or nauseous flavoring. The disadvantage of the carbon element is that its capacity is only 60 gallons. While the ceramic element is rated for 14,000 gallons. But this combination would make it the best filter for emergencies, in situations where additional carbon elements can still be obtained when needed. The COMBI can be operated without the carbon element if needed.
SweetWater has been the innovator of good, economical water filters. And they have been the leader in trying to set standards for water filters and purifiers. The SweetWater products remove 99.9999% of the disease-causing waterborne bacteria.
The SweetWater Guardian Microfilter System uses a 0.2 micron microfilter to protect against giardia, cryptosporidium, and bacteria. With the addition of their ViralGuard cartridge, it becomes a complete water purifier, by chemically treating the water to kill disease-causing viruses. The Guardian will handle up to 200 gallons before the filter needs to be replaced. The ViralGuard cartridge will handle about 90 gallons of water. The SweetWater replacement filters are very economical. The Guardina+Plus includes the ViralGuard. I recommend the Guardian (or the Guardian+Plus) for emergencies, where the initial purchase price is a factor.
SweetWater has recently introduced their WalkAbout as a lower priced unit with the same filtering capability as the Guardian, but will only handle 100 gallons before filter replacement. This is the least I would recommend that everyone have to be able to handle short term emergencies, or for outdoor camping and similar activities.
I hope this provides you with enough information to make the right selection of water filters for your anticipated needs and finances.