We've done a lot of reviews of different portable water filters over the years. I covered the basics of how to choose a filter a while back (although I can't find the article now) and lamented the fact that I had to use the claims of the manufacturers because I no longer have access to a water quality control lab. Well, someone with more money than I have has finally sent a batch of commercially available, common water filters to a testing lab and has published the results.
Widener's is an outdoors supply house that has been around for a while. I've bought a selection of reloading equipment and supplies from them over the years, but have no financial interest in the company. They decided to test some of the common water filters and compare the results to the claims made by the makers and the results were interesting but not surprising. The full article (and it's a long read) can be found here, but I'll recap the highlights:
- They do a fine job of going over the reasons for wanting a water filter and the possible contaminants.
- They also did and excellent job of describing how filters work and the difference in the systems on the market.
- They go over the pros and cons of the various types of filters (straws, gravity, inline, pumped, etc) and then they start the testing of 17 filters.
Most of the filters did poorly on removing viruses, but did a good job on bacteria and cysts; cysts and protozoa are a concern in remote areas where animals use the water supply you're looking at. The results were listed in “log” format; basically, the “log” number is a logarithmic representation of how close to 100% a result is; log 3= 99.9%, log 4=99.99%, log 5= 99.999% and so on.
Here are the filters and the results:
- A “white label” filter made in China.
- Log 6 removal of bacteria, log 4 for cysts, < 50% for viruses.
- Inconsistent claims in their advertising about effectiveness, but it worked for bacteria and cysts.
- Stainless steel reservoirs and black filter element.
- Sold as the Berkey Go kit that includes the Berkey bottle, below.
- Log 6 removal of bacteria, log 4 for cysts, log 3 for viruses.
- Virus removal was not quite as advertised, but still good.
- Log 6 removal of bacteria, log 4 for cysts, < 50% for viruses.
- Advertised as a “purifier”, but doesn't meet the criteria for that designation due to the lack of virus removal.
- A “white label” filter made in China and sold under a variety of names.
- Log 6 removal of bacteria, log 4 for cysts (even though they don't advertise it as effective against cysts), and < 50% for viruses.
- A bottle that you fill and then press the filter into to force the water through, like a french press for coffee.
- Log 6 for removal of bacteria, log 4 for cysts, log 4 for viruses.
- The best straw they tested.
- Log 6 removal of bacteria, log 4 for cysts, log 5 for viruses.
Katadyne Hiker
- Log 6 removal of bacteria, log 4 for cysts, < 50% for viruses
- Filter worked as advertised, no deceptive claims.
- The most popular filter on the market.
- Makes no claims or mention of viruses.
- Log 6 removal of bacteria, log 4 for cysts, < 50% for viruses.
- A camp or family filter, cannot be used "on the go."
- Log 6 for removal of bacteria, log 4 for cysts, 100% for viruses.
- The most expensive of all tested filters.
- A “white label” filter that you'll find with many names on the side.
- Log 6 removal of bacteria, log 4 for cysts, < 50% for viruses.
- No claim made for removing viruses.
- Log 6 removal of bacteria, log 4 for cysts, < 50% for viruses.
- Misleading advertising, claims to meet standards that don't apply since it doesn't remove viruses.
- A “white label” filter sold under a variety of brand names.
- Log 6 removal of bacteria, log 4 for cysts, < 50% for viruses.
- Log 6 for removal of bacteria, log 4 for cysts, log 3 for viruses.
- A “white label” Chinese filter sold by a solar power company.
- Log 6 removal of bacteria, log 4 for cysts, < (less than) 50% for viruses.
- Deceptive advertising that states it was “tested” for virus removal, but not that it actually removed any.
- Amazon “Choice” award, but not really worth buying.
- A unique system of three filters that stack up to remove all three threats.
- Log 6 removal of bacteria, log 4 for cysts, 100% of viruses.
- Log 6 removal of bacteria, log 4 for cysts. < 50% for viruses.
- Sawyer states that their filter is not designed to remove viruses.
- A bottle filter that is supposed to use the same filter media as its big brother.
- Log 5 removal of bacteria, log 4 for cysts, < 38.3% for viruses.
- The worst that they tested for viruses, and it didn't meet its other advertised claims.
As you can see, there are some well-known names on that list as well as a few generic filters. I didn't list prices because they change too rapidly. Check the Amazon links for current pricing if you're interested in one of these.
I carry the Sawyer Mini in my bags, but I may look closer at the Renovo system and the H2O Survival travel straws.
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